TECHNICAL INSTRUCTlbN SERIES 




I 





HANDICRAFT SERIES. 

A Series of Practical Manuals. 

Edited by PAUL N. HASLUCK, Editor of '"Work," ''Technical Instruction 

Series," etc. 
Price 50 cts, eachy postpaid. 



House Decoration. Comprising Whitewashing, Paperhanging, Painting, etc. 
With 79 Engravings and Diagrams. 

Contents. — Colour and Paints. Pigments, Oils, Driers, Varnishes, etc. Tools used by 
Painters. How to Mix Oil Paints. Distemper or Tempera Painting. Whitewashing 
and Decorating a Ceiling. Painting a Room. Papering a Room. Embellishment of 
Walls and Ceilings. 

Boot Making and ^lending. Including Repairing, Lasting, and Finishing. With 
179 Engravings and Diagrams. 

Contents. — Repairing Heels and Half-Soling. Patching Boots and Shoes. Re-Welting 
and Re-Soling. Boot Making. Lasting the Upper. Sewing and Stitching. Making 
the Heel. Knifing and Finishing. Making Riveted Boots and Shoes. 
How to Write Signs, Tickets, and Posters. With 170 Engravings and Diagrams. 

Contents. — The Formation of Letters, Stops, and Numerals. The Signwriter's Outfit. 
Making Signboards and Laying Ground Colours. The Simpler Forms of Lettering. 
Shaded and Fancy Lettering. Painting a Signboard, Ticket-Writing. Poster-Paint- 
ing. Lettering with Gold, etc. 

Wood Finishing. Comprising Staining, Varnishing, and Polishing. With Engrav- 
ings and Diagrams. 

Contents. — Processes of Finishing Wood. Processes of Staining Wood. French Polish- 
ing. Fillers for Wood and Filling In. Bodying In and Spiriting Off. Glazing and 
Wax Finishing. Oil Polishing and Dry Shining. Re-polishing and Reviving. Hard 
Stopping or Beaumontage. Treatment of Floors-Stains. Processes of Varnishing Wood 
Varnishes. Re-polishing Shop Fronts. 
Dynamos and Electric 3Iotors. With 142 Engravings and Diagrams. 

Contents. — Introduction. Siemens Dynamo. Gramme Dynamo. Manchester Dynamo. 
Simplex Dynamo. Calculating the Size and Amount of Wire for Small Dynamos. 
Ailments of Small Dynamo Electric Machines: their Causes and Cures. Small Electro- 
motors without Castings. How to Determine the Direction of Rotation of a Motor. 
How to Make a Shuttle-Armature Motor. Undertype 50-Watt Dynamo. Manchester 
Type 440-Watt Dynamo. 
Cycle Building and Repairing. With 142 Engravings and Diagrams. 

-Contents. — Introductory, and Tools Used. How to Build a Front Driver. Building a 
Rear-driving Safety. Building Tandem Safeties. Building Front-driver Tricycle. Build- 
ing a Hand Tricycle. Brazing. How to Make and Fit Gear Cases. Fittings and Accesso- 
ries. Wheel Making. Tires and Methods of Fixing them. Enamelling. Repairing. 
Decorative Signs of All Ages for All Purposes. VV ith 277 Engravings and Diagrams. 

Contents. — Savage Ornament. Egyptian Ornament. Assyrian Ornament. Greek 
Ornament. Roman Ornament. Early Christian Ornament. Arabic Ornament. Celtic 
and Scandinavian Ornaments. Mediaeval Ornament. Renascence ajid Modern Orna- 
ments. Chinese Ornament. Persian Ornament. Indian Ornament. Japanese Ornament. 
Mounting and Framing Pictures. With 240 Engravings, etc. 

Contents. — Making Picture Frames. Notes on Art Frames. Picture Frame Cramps. 
Making Oxford Frames. Gilding Picture Frames. Methods of Mounting Pictures. 
Making Photograph Frames. Frames covered with Plush and Cork. Hanging and 
Packing Pictures. 

Smiths' Work. With 211 Engravings and Diagrams. 

Contents. — Forges and Appliances. Hand Tools. Drawing Down and Up-setting. 
Welding and Punching. Conditions of Work: Principles of Formation. Bending and 
Ring Making. Miscellaneous Examples of Forged v\ ork. Cranks, Model Work, and 
Die Forging. Home-made I'orges. The Manipulation of Steel at the Forge. 

Glass Working by Heat and Abrasion. With 300 Engravings and Diagrams. 

Contents. — Appliances u.sed in Glass Blowing. Manipulating Glass Tubing. Blowing 
Bulbs and Flasks. Jointing Tubes to Bulbs forming Thistle Funnels, etc. Blowing and 
Etching Glass Fancy Articles; Embossing and Gilding Flat Surfaces. Utilising Broken 
Glass Apparatus; Boring Holes in, and Riveting Glass. Hand-working of Telescope 
Specula. Turning, Chipping, and Grinding Glass. The Manufacture of Glass. 

DAVID McKAY. Publisher, 1022 Market Street, Philadelphia. 



HANDICRAFT SERIES {continued). 



Building Model Boats. With 168 Engravings and Diagrams. 

Contents. — Building Model Yachts. Rigging and Sailing Model Yachts. Making and 
Fitting Simple Model Boats. Building a Model Atlantic Liner. Vertical Engine for a 
Model Launch. Model Launch Engine with Reversing Gear, Making a Show Case for 
a Model Boat. 

Electric Bells, How to Make and Fit Them. With 162 Engravings and Diagrams. 
Contents. — The Electric Current and the Laws that Govern it. Current Conductors 
used in Electric-Bell Work. Wiring for Electric Bells. Elaborated Systems of VViring; 
Burglar Alarms. Batteries for Electric Bells. The Construction of Electric Bells, Pushes, 
and Switches. Indicators for Electric-Bell Systems. 

Bamboo Work. With 177 Engravings and Diagrams. 

Contents. — Bamboo: Its Sources and Uses. How to Work Bamboo. Bamboo Tables. 
Bamboo Chairs and Seats. Bamboo Bedroom Furniture. Bamboo Hall Racks and Stands. 
Bamboo Music Racks. Bamboo Cabinets and Bookcases. Bamboo Window Blinds. 
Miscellaneous Articles of Bamboo. Bamboo Mail Cart. 

Taxidermy. With 108 Engravings and Diagrams. 

Contents. — Skinning Birds. Stuffing and Mounting Birds. Skinning and Stuffing 
Mammals. Mounting Animals' Horned Heads: Polishing and Mounting Horns. Skin- 
ning, Stuffing, and Casting Fish. Preserving, Cleaning, and Dyeing Skins. Preserving 
Insects, and Birds' Eggs. Cases for Mounting Specimens. 

Tailoring. With 180 Engravings and Diagrams. 

Contents. — Tailors' Requisites and Methods of Stitching. Simple Repairs and Press- 
ing. Relining, Repocketing, and Recollaring. How to Cut and Make Trousers. How 
to Cut and Make Vests. Cutting and Making Lounge and Reefer Jackets. Cutting and 
Making Morning and Frock Coats. 

Photographic Cameras and Accessories. Comprising How to Make Cameras, 
Dark Slides, Shutters, and Stands. With 160 Illustrations. 
Contents. — Photographic Lenses and How to Test them. Modern Half-plate Cameras. 
Hand and Pocket Cameras. Ferrotype Cameras. Stereoscopic Cameras. Enlarging 
Cameras. Dark Slides. Cinematograph Management. 

Optical Lanterns. Comprising The Construction and Management of Optical 
Lanterns and the Making of Slides. With IGO Illustrations. 
Contents. — Single Lanterns. Dissolving View Lanterns. Illuminant for Optical Lan- 
terns. Optical Lantern Accessories. Conducting a Lime-light Lantern Exhibition. Ex- 
periments with Optical Lanterns. Painting Lantern Slides. Photographic Lantern 
Slides. Mechanical Lantern Slides. Cinematograph Management. 

Engraving Metals. With Numerous Illustrations. 

Contents. — Introduction and Terms used. Engravers' Tools and their Uses. Ele- 
mentary Exercises in Engraving. Engraving Plate and Precious Metals. Engraving 
Monograms. Transfer Process of Engraving Metals. Engraving Name Plates. En- 
graving Coffin Plates. Engraving Steel Plates. Chasing and Embossing Metals. Etch- 
ing Metals. 

Basket Work. With 189 Illustrations. 

Contents. — Tools and Materials. Simple Baskets. Grocer's Square Baskets. Round 
Baskets. Oval Baskets. Flat Fruit Baskets, vv icker Elbow Chairs. Basket Bottle- 
casings. Doctors' and Chemists' Baskets. Fancy Basket Work. Sussex Trug Basket. 
Miscellaneous Basket Work. Index. 

Bookbinding. With 125 Engravings and Diagrams. 

Contents. — Bookbinders' Appliances. Folding Printed Book Sheets. Beating and 
Sewing. Rounding, Backing, and Cover Cutting. Cutting Book Edges. Covering 
Books. Cloth-bound Books, Pamphlets, etc. Account Books, Ledgers, etc. Coloring, 
Sprinkling, and Marbling Book Edges. Marbling Book Papers. Gilding Book Edges. 
Sprinkling and Tree Marbling Book Covers. Lettering, Gilding, and Finishing Book 
Covers. Index. 

Bent Iron Work. Including Elementary Art Metal Work. With 269 Engravings 
and Diagrams. 
Contents. — Tools and Materials. Bending and Working Strip Iron. Simple Exercises 
in Bent Iron. Floral Ornaments for Bent Iron Work. Candlesticks. Hall Lanterns. 
Screens, Grilles, etc. Table Lamps. Suspended Lamps and Flower Bowls. Photo- 
graph Frames. Newspaper Rack. Floor Lamps. Miscellaneous Examples. Index. 

Other Volumes in Preparation, 
DAVID McKAV, Publisher, 1022 Market Street, Philadelphia. 



TECHNICAL INSTRUCTION. 

Important New Series of Practical Volumes. Edited by PAUL N. HASLUCK. 
With numerous Illustrations in the Text. Each book contains about 1 60 pages, 
crown 8vo. Cloth, $1.00 each, postpaid. 

Practical Draughtsmen's Work. With 226 Illustrations. 

Contents. — Drawing Boards. Paper and Mounting. Draughtsmen's Instruments. 
Drawing Straight Lines. Drawing Circular Lines. Elliptical Curves. Projection. 
Back Lining Drawings. Scale Drawings and Maps. Colouring Drawings. Making a 
Drawing. Index. 

Practical Gasfltting. With 120 Illustrations. 

Contents. — How Coal Gas is Made. Coal Gas from the Retort to the Gas Holder. 
Gas Supply from Gas Holder to Meter. Laying the Gas Pipe in the House. Gas 
Meters. Gas Burners. Incandescent Lights. Gas Fittings in Workshops and Theatres. 
Gas Fittings for Festival Illuminations. Gas Fires and Cooking Stoves. Index. 

Practical Staircase Joinery. With 215 Illustrations. 

Contents. — Introduction: Explanation of Terms. Simple form of Staircase — Housed 
String Stair: Measuring, Planning, and Setting Out. Two-flight Staircase. Staircase 
with Winders at Bottom. Staircase with Winders at Top and Bottom. Staircase with 
Half-space of Winders. Staircase over an Oblique Plan. Staircase with Open or Cut 
Strings. Cut String Staircase with Brackets. Open String Staircase with Bull-nose 
Step. Geometrical Staircases. Winding staircases. Ships' Staircases. Index. 

Practical Metal Plate Work. With 247 Illustrations. 

Contents. — Materials used in Metal Plate Work. Geometrical Construction of Plane 
Figures. Geometrical Construction and Development of Solid Figures. Tools and 
Appliances used in Metal Plate Work. Soldering and Brazing. Tinning. Re-tinning, 
and Galvanising. Examples of Practical Metal Plate Work. Examples of Practical 
Pattern Drawing. Index. 

Practical Graining and 3Iarbling. With 79 Illustrations. 

Contents. — Graining: Introduction, Tools and Mechanical Aids. Graining Grounds 
and Graining Colors. Oak Graining in Oil. Oak Graining in Spirit and Water Colors. 
Pollard Oak and Knotted Oak Graining. Maple Graining. Mahogany and Pitch-pine 
Graining. Walnut Graining. Fancy Wood Graining. Furniture Graining. Imitating 
Woods by Staining. Imitating Inlaid Woods. Marbling: Introduction, Tools, and 
Materials. Imitating Varieties of Marble. Index. 

Ready Shortly : 
Practical Plumbing Work. 

Other New Volumes in Preparation, 

DAVID McKAY, Publisher, 1022 Market Street, Philadelphia. 



PRACTICAL DRAUGHTSMEN'S WORK 



PRACTICAL 
DRAUGHTSMEN'S WORK 



WITH NUMEROUS ENGRAVINGS AND DIAGRAMS 



EDITED BY 

PAUL N. HASLUCK 

HONOURS MEDALLIST IN TECHNOLOGY 

EDITOR OF "work" AND "BUILDING WORLD" 

ADTHOa OF " HANDYBOOKS FOR HANDICRAFTS," ETC. ETO. 



DAVID M( KAY, Publishkr 

1022 MARKET STREET 
a903 






M-H 



T 



ij ; — 



^^(?a t 



05 



PREFACE. 



Practical Draughtsmen's Work contains, in a form con- 
venient for everyday use, a comprehensive digest of information, 
contributed by experienced draughtsmen, scattered over the 
columns of Work and Building World, two weekly journals 
it is my fortune to edit, and supplies concise information on the 
general principles and practice of the art on which it treats. 

In preparing for publication in book form the mass of relevant 
matter contained in the volumes, much of it necessarily had to 
be re-arranged and re-written. The contents of this book con- 
sist substantially of several series of illustrated articles by Prof. 
Henry Adams, originally contributed to Work and Building 
World. The writings of many other contributors are so 
blended that it is difficult to distinguish any for acknowledg- 
ment. 

Headers who may desire additional information respecting 
special details of the matters dealt with in this book, or instruc- 
tion on any building trade subjects, should address a question to 
Work or Building World, so that it may be answered in the 
columns of one of those journals. 

P. N. HASLUCIv. 



CONTENTS. 



I. — Drawing Boards, Paper and Mounting 
II. — Draughtsmen's Instruments 
III. — Drawing Straight Lines . . <, 
IV. — Drawing Circular Lines . , 

V. — Elliptical Curves . . • , 
VI. — Projection ..... 
VII. — Back-lining Drawings 
VIII. — Drawing to Scale and Preparing Maps 
IX. — Colouring Drawings 
X. — Making Drawings . . • . 
Index 



PAGE 

9 

19 

37 

52 

70 

92 

104 

114 

126 

140 

156 



LIST OF ILLUSTRATIONS. 



FIO. 
L 

2. 
3. 
4. 



PAGE 

—Back of Battened Drawing- 
board 10 

—Clamped Drawing-board . . 10 
, — Corner of Drawing-board . .11 
, — Position of Draughtsman's 

Board 12 

.—Section of Fixed Table and 

Board 13 

-11. — Drawing Pins . . .16 
.—Pasting Margin of Drawing- 
paper 17 

—Fastening the Paper . . .17 
—Edge and Top View of T-square 20 
— Fiamed Set-square . . .21 
, — Set-square for Lettering . . 21 
—Use of T- and Set-squares . 22 
, — Serviceable Set of Instruments 23 
—Ruling Pen .... 24 
—Lift-up Nib .... 25 
— Square-handled Pen . . . 25 
, —Double Ruling Pen . . .25 
,— Pen for Ruling Curves . . 25 
,— Milled Head between the Nibs 26 
—Setting Ruling Ptn ... 26 
,— Point of Ruling Pen Enlarged . 26 
—Dotting Pen . . . .27 
,— Dotting Pen with Midrib . . 27 
-32. —Needle Points for Compasses 28 
—Socket Fitting for Compass Legs 29 
— Leg of Hair Dividers. . . 30 
—Proportional Compasses . . 30 
, — Bow Compass . . . .31 
. — Spring Bow Dividers. . . 31 
. — Spring Bow Pencil . . .31 
—Spring Bow Pen. ... 31 
— Pump Bows . . . .32 
— Spring Bows . , . .32 

—Pen Point 33 

—Back of Holder . ... 33 
— Section through Beam . . 33 
—Needle Point . . . .33 
— Cheap Beam Compass . . 34 

— Curve Bow 34 

— Railway Curve . . . .35 
-51. — French Curves . . .35 
— Method of Holding T-square . 37 
—Chisel Shaped Pencil Point . 38 
—Round Point to Pencil . . 38 
—Method of Holding Pencil . 39 
— Line in Error . . . .39 
—Dotted Line .... 39 
— Testing Straightedge . .40 

— Untrue T-square makes Correct 

Angles 40 

—Untrue Board makes Incorrect 
Andes 41 



FIG. PAGK 

61. — Testing Set-square . . .42 
62.— Straightening Set-square Edge. 43 
63, 64. — Parallel and Perpendicular 

Lines . . . . 43, 44 
65.— Equal Lines Appear Unequal . 44 
66.— Equal Spaced Spots Appear 

Unequal. . . . .'45 
67.— Straight Lines Appear Curved. 45 
68.— Paralleled Lines Appear to Con- 
verge and Diverge . '. . 46 
69. — Square Partly Covered . . 46 
70, 71.— Equal Size Areas Appear 

Unequal 47 

72. — Disappearing Dots . . .47 
73-75.— Square Figures ... 48 

76.— Full Lines 49 

77.— Dotted Lines . . . .49 
78.— Dimension Lines , . . 49 
79.— Method of Showing Dimensions 50 
80. — Section Lines . . . .50 
81 —Graduated Lines . . . 50 
82.— Holding Ruling Pen ... 51 
83.— Concentric Circles . . .52 
84.— Finding Centre of Circle . . 53 
85.— Flat Curves . . . .54 
86. — Holding Compasses . . .54 
87. — Sharp Curves .'. ... 54 
88.— Concentric Arcs . . .55 
89.— Arcs of Equal Radius . . 55 
90. — Finding Centre of Small Arc . 50 
91-93.— Circles for Practice . . 56 
94.— Hollow Edge of Castings . . 57 
95. — Angle of Castings . , .58 
96.— Curves Joining Arms and Boss 

of Wheel .... 59 
97.— Example Requiring Accuracy . 60 
98. — Round Corners . . . .61 
99.— Parallel Lines Joined by Semi- 
circle 61 

100. — Angular Lines Joined by Arcs . 61 

101-103 Curved Lines as Junctions 62 

104. — Curved Joins . . . .63 

105.— Ogee Curve 63 

105-113.— Mouldings . . . Qi, 65 
114-121.— Arches. . . . 66-6$ 
122. — Method of using Pump Bow . 69 
123. — Conic Sections . . . .70 

124.— Circle 71 

125.— Ellipse 71 

126.— Vertical Straight Line . . 71 
127-132.— Ellipses . . . 72-76 
133.— Paper Trammel . . . .77 
134. — Use of French Curve . . .77 
135. — Patternmakers' Ellipse . . 7S 
136.— Gardeners' Ellipse . . .79 
137.— Plan of Skew Arch ... 79 



PEAGTIGAL BUAUGHTSMEN'S WORK, 



no. PAGE 


FIG. 


338.— Elevation of Skew Arch . . SO 


190.- 


139, 140.— Flat or Camber Arch . 82, 83 




141, 142. -Parabolas . .• . 84,85 


191.- 


143-145.— Hyperbolas . . . S7, 88 


192.- 


146, 147.— H3l»x . , , , 88, 89 


193-.- 


148.— Entasis of Column . . . 90 


194.- 


149-153.— Proiections of Line . . 92, 93 


195.- 


154, 155.— Pr().iections of Line . . 94, 05 


196. 


156, 157.— Brick in Angular Projection 96 




158.— Grating in Angular Projection. 07 


197.- 


159.— Side Elevation of House . . 99 


198. 


160.— Front Elevation of House . 99 




161.— Angular Projection of House . 99 


199.- 


162, 163.— Cube 100 




164.— Constructing Isometric Scale . 100 


200, 


165.— Isometric Scale . . . .101 


202. 


166.— L«ometric Projection. . .101 


203.- 


167, 168.— Projection at Angle of 45^. 


204- 


102, 103 


205, 


169-172. -- Plans and Elevations of 


207.- 


Rectangular Objects . . 105 


208.- 


173-175.— Plans and Elevations of 


209. 


Curved Objects . . .107 


210. 


176.— Cast Iron Grating . . .108 


211.- 


177.— Chequered Plate . . .110 


212. 


178.— Fluted Pilaster . . . .112 


21.3. 


179.— Fluted Column . . . .113 


214. 


180.— Quarter Scale . . . .110 


215. 


181.— Twelfth Scale . . . .116 


216. 


182.- Forty-eighth Scale , . .117 


217. 


183. — One - hundred - and - twentieth 


218. 


Scale 117 


219, 


184.— Ninety-sixth Scale . . .118 


221. 


185.— Two - thousand - five - hundred th 


222. 


Scale 118 




186, 187.— Scale Drawings . . .119 


223. 


ISS.— Sketch Plan of House . .119 


224. 


189. — Diagonal Scale for Accurate 


225, 


Measurements . , .120 


« 



PAOl 

—Plan to Scale showing Tenths 

and Hundredths . . . 120 
-Plan to Scale : 1 in. = 880 ft. . 122 
J.— Plan to Scale : 1 in. = 88 in. . 122 
-Plan to Scale: 1 in. =208-33 ft. 123 
-Plan to Scale : 1 in. = 41 66 ft. 124 
-Slant and Saucers for Colours . 127 
-Primary Colours and Secondary 

Tints 128 

'. — Colours of the Spectrum . . 130 
-Front Elevation showing Deal 

or Fir 133 

-Side Elevation showing Deal or 

Fir 133 

, 201.— End Grain . . . 133, 134 
1.— Various Cross Sections fur Fir 136 
I. — Front Elevation showing Oak . 136 

-Side Elevation showing Oak 
, 206.— End Grain Oak . 
'. — Cross Sections for Oak 
5. — Marking Measurements . 

- Block Plan of Building and Site 143 
-Measuring Angle . . . 144 
-Scale for Plan shown at Fig. 209 144 
-Sample Block Letters . . 145 
-Enlarged Drawing of Letter G . 145 

[. — Samples of Figures . 

- Plan of House .... 
>. — Front Elevation of Hou.se 

-Side Elevation of House . 

I.— Back Elevation of House . 

, 220. -Sections of House . . __. 
-Irregular Outline to be Copied 148 
-Method of Copying Irregular 

Outline 143 

-Small Squared Plan of Estate . 150 
-Method of Enlarging by Squares 150 

, 226. - Conventional Signs used by 

Draughtsmen . . 152, 153 



136 
137 
137 
141 



146 
147 
147 
147 
147 
147 



PRACTICAL 
DRAUGHTSMEN'S WORK. 



CHAPTER I. 

DEAWING BOARDS, PAPER AND MOUNTING 

This book deals with the principles upon which mechanical and 
architectural drawings are made, and it is proposed, in the 
following chapters, to give a course of practical instruction in 
technical drawing as applied to the constructive arts. This 
branch of drawing does not aim at producing pictures so much as 
at showing conventional representations which shall enable other 
persons to construct precisely and exactly what the designer 
intends, in shape, size, and arrangement. The primary essentials 
are accuracy and neatness. An inaccurate drawing invites bad 
workmanship, and one not neatly made at the least leaves a 
doubt as to what is required. 

Though it may occur in business that »many things have 
to be hurried over for want of time, in learning a subject the 
student should not be satisfied unless each portion of his work is 
an improvement upon the last, and is the very best he is able to 
do ; speed can always be superadded to accuracy if the latter is 
mastered first, but the order can never be reversed. 

To describe the principles involved in making a mechanical 
or architectural drawing would necessitate a treatise on plane 
and solid geometry and projection that would be out of place 
in a book which is intended to deal only with the practical 
operations of the drawing- office. How^ever, it should be under- 
stood that, to be in a position to do any but the very simplest 
work, a certain amount of geometrical knowledge is a necessary 
part of the draughtsman's equipment, and this must be acquired 
by a systematic study of that branch of science. 

To commence draughtsmen's work a large assortment of 



10 



FH ACTIO AL DRAUGHTSMEN'S WOB-K. 



instruments is unnecessary, and even undesirable, the fewer and 
the simpler they are the better, provided they are efficient. Of 
course, a drawing-board, a T-square, and two set squares will be 
required, with drawing pencils, indiarubber, and drawing pins for 
holding down the paper, which may be cartridge paper. If a 
drawing-board 16 in. by 22| in. is employed, sheets 15 in. by 22 in. 
(half imperial size) will be found suitable. The ordinary draw- 
ing instruments, including bows for ink and pencil, will be 
required ; but when the reader has mastered the contents of this 
book he will be able to decide for himself here. We need go no 
further than to advise a beginner not to buy cheap tools. A set of 
pear wood French curves, a foot rule, or a set of scales, will be handy, 
while, for those who prefer it, a steel scale can be obtained. 





Fig. 1. — Back of Battened 
Drawing Board. 



Fig. 2.— Edge of Clamped 
Drawing Board. 



The first thing necessary is a drawing-board, which should 
be made about an inch longer each way than the largest sheet 
of paper in general use. If the sizes of the drawings vary 
considerably, it will be convenient to have large and small boards 
to suit. The usual method of constructing the ordinary board 
is shown in Fig. 1. The wood should be fairly stout, but 
not too hard, so that the pins can be inserted and withdrawn with 
moderate ease ; the grain should run lengthways of the board. 
The two battens should be screwed on underneath, and trans- 
versely to the grain of the other wood, to stiffen the board and 
prevent warping. All woodwork in course of time shrinks to a 
greater extent across the grain than it does in the direction of 
the grain, so it is advisable for the screws securing the battens 
to the board to work in slots, as shown on an enlarged scale in 
Fig. 2. The board is thus allowed to shrink and swell without 
unduly straining the screws or battens. In properly seasoned 
timber the shrinkage will be slight, and care should be used 
to secure wood suitable lor the purpose. To prevent warping 



DRAWING BOARDS, PAPER AND MOUNTING. 11 

through expansion and contraction, drawing-boards are some- 
times grooved on the back, half-way through the thickness, at 
intervals of about Sin. or 4 in. from end to end, as shown in 
Fig. 1. Some boards have hardwood slips glued into grooves at 
the end, as shown by Fig. 3. These slips are to guide the 
stock of the T-square, and saw^ kerfs should be run through 
them at intervals of about 3 in. (b b. Fig. 3) to prevent the slips 
being forced out of position by unequal shrinkage. Smaller 
boards can be stiffened by clamping a strip of wood about 2 in. 
wide transversely on each end of the board, as shown in Fig. 2. 




Fig. 3. — Enlarged Corner of Drawing Board. 

All drawing-boards should be planed level on both sides, and 
squared exactly so that the opposite edges are parallel, and the 
adjacent ones at right angles to each other. A drawing-board 
that has suffered from rough usage and become indented may 
be renovated and the bruised grain of the wood can be raised 
by well wetting it and placing on the dents several thicknesses 
of brown paper previously soaked in hot water. A piece of dry 
paper is placed on these, and a hot flat-iron laid on the whole 
causes the dents to swell up. When the board is dry, a shaving 
or two can be taken off with a smoothing-plane, and the board 
will be as good as new. 

Draughtsmen generally prefer to stand to their work, because 
in the various operations of drawing and finishing a large plan 
operations are seldom confined to one part of the paper only, 
and it is necessary to alter continually the position of the body 
to obtain a proper command of the work. However, for some 
drawing it is possible to work while seated, and a stool is used 
by some draughtsmen. 



12 



PRACTICAL DRAUGHTSMEN'S WORK. 



The position and arrangement of the office in which the 
draushtsman has to work is a matter of some importance. For 
working in the daylight, a window facing north, with the light 
rather on the left-hand side of the board, as shown at Fig. 4, is 
about the best arrangement, and when artificial light is employed 
the lamp should be placed over and beyond the top left-hand 
corner of the board. A pair of supports for inclining the board 
from 15° to 20^ by placing one under each end, as shown in 
Fig. 4, is a convenience. This slope of the board allows the 




Fig. 4. — Position of Draughtsman's Board. 

draughtsman to work with greater ease, especially at the far side 
of the board. 

The height of the desk or table on which the drawing-board 
has to be placed while the draughtsman is at work will be 
determined by the size of the drawings. When the paper is 
under imperial size, one may sit down while at work, and a 
height of about 2 ft. 6 in. from the floor to the surface of the 
drawing-board at its lowest edge, with the board sloping at an 
angle of about \\ in. in a foot, will be a convenient arrangement 
for most workers. With larger drawings the draughtsman will 
find it most convenient to stand while at work ; and to reach 
the upper farther part of the board it will be necessary to use a 



DRAWING BOARDS, FAPER AND MOUNTING. 13 



footstool. Fig. 5 gives a section through a fixed desk or counter 
for a drawing-office. The space underneath is often utilised by 
being fitted with drawers to hold drawings ; but when this 
is done, sufficient knee room should be allowed, by keeping the 
fronts of the drawers well back from the edge of the desk. 
When the drawing-board 'is placed on this desk, the slope for 
convenient working may be obtained by placing under the back 
edge a strip of wood about 2^ in. square (a, Fig. 5), and as long 
as the board, the slope of which may be regulated by sliding this 
strip backwards or forwards. 




777777777777777777777777//^ 

Fig. 5.— Section of Fixed Table and Board. 

The paper most suitable to be used depends a great deal on 
the kind of drawings to be made. For fine, accurate work 
smooth or medium surface paper is the best. But for a coloured 
drawing made more for show than accuracy, rough paper should 
be used, as the colour runs better on it. The papers in general 
use in the drawing office are " cartridge," a machine-made paper, 
used for work where an ordinary finish is required ; and hand- 
made for superior work. Generally one side of the " cartridge " 
is finished to a smoother surface than the other, and the smooth 
surface is the one usually chosen for drawing on ; it is not 
suitable for colouring. Hand-made paper is of a finer and 
stronger texture, and has a hard surface. Both sides are much 
alike in appearance, but the surface intended for drawing on 



14 



FliAGTWAL DRAUGHTSMEN'S WORK. 



may be ascertained by holding the paper up to the light and 
observing the letters of the water-mark, which reads in the 
right direction when looked at from the working surface. 
For drawings which have to be submitted to much handling, or 
which it is desired to preserve in good condition for many years, 
it is usual to use drawing-paper mounted on holland or linen. 

The sizes of drawing-papers vary to the extent of half an 
inch or so with dififerent makers, but the usual sizes are as 
follows : — 

USUAL SIZES OF DRAWING-PAPER. 





WHATMAN'S. 


JOTNSON'S. 


Name of Paper. 


Sizo- to 
Inches. 


lb. weight 
to Beam. 


Size to 
Inches. 


lb. weight 
to Ream. 


Foolscap ... 
Demv 


17 X 13i 

20 X 15^ 


18 
25 


20 X 154 


42 


Medium 


22 X 174 


34 


— 


— 


Royal 


24 X 19 


44 


24 X 19 


44 to 60 


Super Royal 

Elephant 

Imperial 

Colombier 


27 X 19 

28 X 23 
304 X 224 


54 

72 

72 


30 X 22 


72 to 140 


344 X 234 


100 


— 


— 


Atlas 


34 X 26 


100 


— 


— 


Double Elephant... 
Grand Eagle 


40 X 26J 
42^ X 28 


133 
150 


40 X 27 


140 to 230 


Antiquarian 


53 X 31 


240 


52i X 30^- 


250 


Emperor 


— 


— 


72 X 48 


535 


Double Emperor ... 


— 


— 


96 X 69 


1025 



These papers can be obtained in three surfaces— N (natural 
surface), HP (hot pressed or smooth surface), R (rough surface). 
The natural-surface paper should be employed for general work, 
as it will stand much rubbing out and will take colour well. 
The hot-pressed surface paper is the best for fine pencil and ink 
drawings that are not coloured. The rough paper is used by 
artists for water-colour drawings and sketches. 

Paper of the standard sizes is to be bought ready mounted 
on cloth, and for specially large plans either "cartridge" or 
superior paper can be bought in a continuous roll in various 
widths up to 60 in. 



DRAWING BOARDS, PAPER AND MOUNTING. 15 

A useful paper is that sold ready divided by faintly ruled 
lines into squares of various sizes, generally into inches and 
eighths or tenths, the inches themselves being indicated by a 
thicker line. It is of service in enlarging or reducing by the 
method of squaring described on p. 150, and even more so in 
sketching directly to scale, as the squares enable any dimension 
to be drawn correctly at once. It is applicable alike to the uses 
of the machine draughtsman in sketching details of machinery 
to correct scale and the civil engineer for plotting small surveys. 

Tracing-papers are made in a variety of thicknesses, tints, 
and textures. They have usually one side smoother than the 
other, and are sold in continuous rolls measuring 21 yd. or 22 yd. 
in length, and varying in width from 30 in. to 44 in. To make 
tracing-paper tissue paper is coated, by brushing or sponging, 
with a mixture of 1 part of boiled linseed oil to 5 parts of 
turpentine. Each sheet is done separately, and hung over a line 
to dry. When the clear oily marks disappear it will be ready 
for use. Tracing-linen or tracing-cloth is obtainable in about 
the same sizes. It is made generally with one side glazed and 
the other rough, and occasionally with both sides glazed. The 
selection of the side to be used for drawing on must be 
left to individual discretion, some preferring one side, some the 
oth^r. The rougher side is easier to work on, as it takes both 
ink and colour easily, but a much neater and more effective 
tracing is produced on the glossy side, the colouring being done 
on the rough surface. The rougher surface is more easily soiled 
than is the smooth. 

It is a usual custom, before commencing a mechanical draw- 
ing, to secure the paper to a drawing-board, so as to keep it flat 
and in the same position relative to the edges of the board 
from which right angles are set off with the T-square. The most 
simple method is by placing lead weights on the corners of the 
paper. If the drawing is to be made in pencil only, then the 
paper can be fastened to the board by pins. The most convenient 
way to do this is to place the paper squarely on the board, and 
put a drawing-pin into the top left-hand corner ; place the 
T-square along the top edge of the paper : take hold of the 
bottom right-hand corner of the paper and move it up or down till 
the top edge of the paper becomes parallel with the edge of the 
T-square, when another drawing-pin can be inserted in the bottom 
right-hand corner, and then two others in the remaining corners. 



/ 



16 PRACTICAL DRAUGHTSMEN'S WORK. 

The principal point to be attended to in the choice of drawing- 
pins (see Figs. 6 to 11), is that the head shall be so shaped as not 
to interfere with the passing of the blade of the T-square over it ; 
and for this reason the dome-shaped head shown in Fig. 7 will be 
found to answer admirably. Another good section of head is 
shown in Fig. 8 ; while the " flat heads," shown in Fig. 9, are not 
so good as the two last mentioned. A cheap and fairly effective 
drawing-pin is now made by punching out of a steel disc a 
tongue, and bending it downwards to form a pin, as shown in 
Fig. 10; while Fig. 11 shows a form in which the three corners of 
a triangular sheet of thin steel are bent downwards to form three 
pins to pass through the paper. For a good drawing-pin, it is 



Fig. 6. Fig. 7. 





Fig. 8. Fig. 9. Fig. 10. Fig. 11. 

Figs. 6 to 11. — Drawing Pins. 

desirable to have the head at least | in. in diameter, and the pin 
not much tapered, or it will not hold tightly in the drawing-board 
and I this is necessary. 

If the drawing to be inked in, coloured, and dimensioned 
is an elaborate one, and likely to be a long time in hand, 
the paper should be strained on the board. To do this, first 
ascertain which is the correct surface for drawing on, and lay the 
paper face upwards on the board, then bend up a margin strip 
J in. to IJ in. wide all round the sheet. Turn over the paper, 
and well damp the back of it with a sponge and cold water 
taking care to leave the margins free from moisture. After 
thoroughly damping, sponge off the superfluous water, and turn 
the paper right side up on the board, taking care not to wet 
any part of the board where the glue or paste for fastening the 
edges has to come. Lay a wooden straight-edge along the paper, 
about 1 in. from the top edge, bend the dry margin over the 
straight-edge, so as to bring the under surface uppermost over 
the straight-edge, and pass over it a brush dipped in hot glue or 
paste (see Fig. 12). Turn the paper back again, and press the 



BRAWING BOARDS, PAPER AND MOUNTING. 17 

glued margin into close contact with the drawing-board. Eemove 
the straight-edge to the left-hand margin of the paper, and glue 
that in the same way, and afterwards proceed to glue down the 
other margins at the right-hand end and bottom edge. 




Fi^. 12. — Pastinof the Margin of Drawing- Paper. 

Now smooth down the paper, commencing in the centre of the 
sheet, with a clean dry handkerchief, working gradually towards 
the edges to expel the air. Then press the glued margins well on 




Fastening the Paper. 



the board with the thumbs, at the same time drawing them 
apart, as shown by the arrows (Fig. 13). This operation should 
be repeated all round the margin, the thumbs being always oppo- 
site each other during the stretching process. Shoemakers' paste, 
which can always be obtained ready-made at any cobbler's shop 
or grindery store, is much stronger than the ordinary paste, but 
shares with that material and gum the defect of taking a long 
time to dry. 



18 PEAGTICAL DRAUGHTSMEN'S WORK 

The wetting of the paper causes it to expand, so that it 
measures more in length and breadth than when dry. As the paper 
dries it will shrink, and as the edges are securely glued to the 
board, the paper will stretch itself very tight and fiat. From this 
it will be understood that the more quickly the gluing is done the 
better, because if there be much delay, the paper will be partially 
dried before the margins are completely stuck. It is advisable to 
leave the board in a horizontal position, not standing on one edge, 
as the moisture may run down to the bottom margin, keeping one 
part of the paper wet longer than another. The drying should not 
be hastened by placing tbe board before a fire, which would pro- 
bably dry the paper unevenly, and pull it into wrinkles. If the 
edges of the paper are not firmly glued to the board when the 
paper begins to shrink, they will be pulled from their sup- 
port, and thus the paper cockled and warped. 

Care must be taken that the drawing-board is not stained 
with ink, or this may get into the damp paper and spoil it. 
Some kinds of wood— teak, for instance — will stain the paper ; 
therefore, when there is any doubt on this point, it is a good plan 
to put a sheet of common paper between the board and the 
drawing-paper. In stretching mounted drawing-paper on the 
board, glue will not be strong enough to hold the edges, and 
small tacks should be used for the purpose. 



19 



CHAPTER 11. 
draughtsmen's instruments. 

In giving a brief description of some of the various instruments 
generally used in the drawing office, it may be advisable to 
remind the reader that it would take up more space than can 
be spared here to even mention and illustrate all the varied 
forms of the numerous instruments which are used by 
draughtsmen. Attention is devoted in this chapter principally 
to such appliances as may be considered comparatively indis- 
pensable. All the instruments generally used will be found 
illustrated and described in the catalogues issued by makers and 
dealers, who point out the several merits which are claimed for 
them. A great number of peculiar instruments and many 
patented articles will also be found in the manufacturers' cata- 
logues, and although these are in many cases very useful in their 
way, most practical draughtsmen manage to do without them, 
and in this chapter it is proposed to deal only with those in- 
struments that are usually necessary in the ordinary work of 
making a drawing. 

Most makers stock three qualities of instruments, and it is 
advisable to buy the best that are made, called extra- quality 
instruments, as they will last a lifetime and the first cost is also 
the last. 

Next in importance to the drawing-board, which has already 
been described in the preceding chapter, comes the T-square. 
Spanish mahogany is the best wood for large squares, and smaller 
ones may be made of pear tree or of mahogany, edged with 
ebony. Plain straight - grained wood should be selected for 
T-squares. Figured mahogany is more liable to warp, is difficult 
to plane, and wears to a ragged edge. The blade ought to be 
easily removable from the stock for the purpose of trueing up the 
edges. 

The most approved pattern of T-square has a taper blade 
screwed on the top of the butt end, as shown by Fig. 14, p. 20. 
A parallel blade let into the butt is not so good. With tiie 



20 PRACTICAL DRAUGHTSMEN'S WORK. 

former the set-square can slide over the butt, and still be kept 
against the blade ; with the latter the set-square must be 
raised to pass over the butt, which makes it difficult to keep the 
set-square firm against the blade. However well seasoned the 
pear-tree or mahogany wood of which the T-squares are made, it 
will be found difficult to prevent it warping, and care should be 
taken to keep the squares in a place free from damp or exces- 
sive heat. The working edges of the butt and blade should be 
furnished with narrow strips of ebony slightly bevelled on the 
upper side. Some T-squares are made with parallel blades and 
shifting stocks, which may be adjusted to any angle. These are 
not popular with practical draughtsmen, who generally prefer to 



lllHlm'i^ 



Edge View of T-square. 




14, — Top View of T-sqaare. 



use two set squares with which to draw lines at an angle. The 
T-square must be worked on the left-hand edge of the drawing- 
board, and it should be used for drawing horizontal lines only ; 
the perpendiculars being always drawn by a set -square working 
against the T-square. A T-square used for vertical as well as 
horizontal lines would communicate to the lines in the drawing 
any slight inaccuracy in the truth of the edges of the board, as 
shown on p. 41. 

The position of the left hand when drawing is shown in Fig. 52, 
p. 37, the left hand holding the set-square against the T-square, 
the thumb and forefinger pressing the blade on the paper, and 
at the same time folding the butt against the end edge of the 
board by a slight pressure towards the right. 

Next in importance to the T-square comes a selection of set- 
squares. These are made of various materials, all of which have 



DRAUGHTSMEN'S INSTRUMENTS, 



21 



certain objectionable features, but the best squares are those made 
of ebonite or vulcanite, as shown in Fig. 17. They are not liable to 
warp or to get out of square, but they collect dirt and smear the 
paper if not kept very clean, are liable to break if dropped or 
roughly handled, and the larger sizes are rather expensive. 
Framed set-squares (see Fig. 15) are made of three pieces of 
mahogany or other wood, edged with ebony. They are built up 
of three separate parallel pieces of hard wood, joined at the 
corners. By means of the open centre, a better hold of the set 
square can be obtained, and it can thus be moved about more 
freely, and held more firmly when once in its proper position 
for drawing. Framed squares are liable to get out of order 
if not made of carefully selected dry material. Common^ plain 





Fig". 15. — Framed Set Square. Fig. 16.— Set Square for Lettering. 

squares, made of plain pieces of thin mahogany, pear-tree, or 
other woods, planed to the required angles, are liable to twist 
and warp when exposed to heat or dampness. 

These squares have a hole, about | in. in diameter, bored 
near the base, by which they can be manipulated, and which 
also enables tbem to be hung on a peg. Set squares are 
made of all angles, but for ordinary work two are generally 
sufficient, one with angles of 30^, G0°, and 90°, and one with 
angles of 45*^, 45^, and 90^\ Special set-squares are procurable, 



22 PRAGTIGAL DBAUGHTMEN'S WGEK. 

adapted to the various pitches of roofs, slopes, and batters of 
embankments, angles of screw nuts, and other standard require- 
ments. A set-square used in setting-out lettering is illustrated 
at Fig. 16. 

When drawing a vertical line, the vertical side of the 
set-square should be turned towards the left, as shown at 
B, Fig. 17. When it is desired to draw lines against the sloping 
edge of the set- square this is reversed, as shown at a. In both 
cases the set-square serves as a rest for the draughtman's hand 
and protects the drawing. 

Drawing pens and compasses form the most important instru- 
ments in the draughtman's outfit. Foreign-made cases of 
instruments, containing a large number of pieces, may be bought 
for a comparatively small sum, but cheap instruments are often 



IXA 



Fig. 17. — Use of T and Set Squares in Drawingf, 

worthless. The best plan is to buy of some well-known maker, 
and get instruments which the makers will guarantee to replace 
if not satisfactory. A case should be provided in which to keep 
the instruments, so that they shall be together and clean. 
Among working draughtsmen it is generally agreed that a 
beautiful, well-polished case crammed with the very best instru- 
ments of all and every kind, is not necessary for turning out a 
good drawing, and good work can be done by means of a few of 
the simplest and plainest instruments. It may not be out of 
place here to give the following hint to young would-be draughts 
men : — Do not waste a lot of money in getting together an 
elaborate and expensive box of instruments, many of which will 
afterwards be found to be not wanted. It is better even to buy 
singly just the instrument that is wanted as advance is nivade in 
the art of drawing. A strip of chamois leather and a pair of 
elastic bands make a case that serves all purposes ; it keeps out 



JDEAUGRTSMEJSl'S INSTRUMENTS. 



23 



the damp and preserves the points, and possesses many distinct 
merits. No draughtsman need ever feel diffidence in walking 
into the best of drawing offices with such a little roll of instru- 
ments in his pocket. Empty cases may be purchased without the 
instruments. Some morocco-covered ones that go in the pocket 
have a neat appearance, take up }>ut little room, and are not 
expensive. It is advisable to commence with a case that will 
contain the following, even if it is not filled up at first :— Half- 




Fig. 18. — Serviceable Set of Instruments. 

set of 6-in. compasses, with lengthening bar ; ink and pencil 
bows ; two drawing pens ; set of three spring-bows ; pricker and 
key. These instruments are sufficient for general work. 

Fig. 18 illustrates the contents of an ordinary box of service- 
able instruments. They comprise, commencing at the upper 
part : — One pair of 6-in. compasses with pencil point ; one pair 
of compasses with pen point ; one pair of 5-in. hair dividers ; 
bow pen ; bow pencil ; set of three spring bows, comprising 
divider, pencil, and pen ; three drawing pens ; pair of beam- 
compass heads with screw adjustment and extra pen and penci 
joints, and screw key for adjusting the joints. 



24 



FRAGTIGAL DRAUGHTSMEN'S WORK. 



1 



M M 



illllll 






pi 



be 



A ruling pen of good quality should be 
selected, as it is the instrument with which most 
of the lines are inked in, see Fig. 19. This illus- 
tration shows a pen fitted with an ink reservoir 
in the handle, and it is particularly useful for 
drawing lines that require much ink. 

Pens with lift-up nibs, as shown at Fig. 20, 
are handy for setting and keeping clean. It is 
advisable to choose a ruling pen having one 
strong and rigid blade which will not bend with 
an increase of pressure against the edge of the 
set -square or straight-edge ; flexibility would 
affect the regular thickness of the line which is 
being drawn. The handle shown in Fig. 21 has 
a square portion which is useful in preserving 
the proper direction of the nibs of the pen 
when drawing. This screw should be sufficiently 
loose for the draughtsman to open or close the 
nibs with the second finger, when holding the pen 
as shown in Fig. 62, p. 51, without lifting it from 
the paper. New pens are usually too tight, and 
a little oil mil greatly improve the working of 
a tight screw, and the screw of all pens and 
spring dividers should be oiled occasionally, or 
in the course of time they may strip their threads. 
It is often convenient to be able to carry a draw- 
ing pen in the pocket ready for use, for much 
can be done with this instrument alone by a 
mechanical draughtsman who is also a good free- 
hand draughtsman. A pocket drawing pen con- 
sists of a hollow handle in which the nib is 
carried secure from damage. When required for 
use, the nib is unscrewed, reversed, and again 
screwed into the handle. 

For drawing parallel lines moderately close 
together, as in indicating roads, canals, or rail- 
ways in maps and small scale plans, a double 
pen, such as is shown in Fig. 22, is conveni- 
ent. It consists of two ruling pens, with a 
screw and a milled head for regulating the 
distance between them. It is particularly 



DBA UGHTSMEN'S INS TR U ME NT 8. 



25 



useful where the lines to be drawn are curved or of irregular 
form. 

A ruling pen especially designed for drawing curved lines is 
shown in Fig. 23. The handle is tubular, and through it there 
runs loosely the metal shank of the pen. At the top is a milled 
head, by which the pen can be clamped tight to the handle, and 
can then be used as an ordinary drawing pen. When the nibs 




Fig. 20.— Lift-up Nib. 



<i|l.Mlljft 



Fig. 21.— Square Handled Pen. 




Fig. 22.— Double Ruling Pen. 




F.g. 28. — Pen for Ruling Curves. 



are free to revolve independently of the handle, they follow the 
direction of a curved line with great freedom, and although 
rather aw^kward to handle without practice, a swivel pen is con- 
venient for the purpose of drawing lines against a curved guide. 

Draughtsmen's ruling pens should always be cleaned after 
using, and for this to be done it is convenient, though not 
necessary, to have one of the nibs hinged so as to lift up and 
allow the dried ink to be scraped off the inner side of the nibs 
with a penknife. This hinge is shown in Fig. 25. A piece of 
chamois leather pulled between the nibs of the pen after using 
it, will generally be found sufficient. For scraping off hard dried 



26 PBAGTIGAL DBAUGHTSMEX'S WORK. 

Indian ink, the thin blade of a penknife may be inserted between 
the nibs of the drawing pen, or a steel writing pen with half 
of the nib broken away may be used. The adjusting screw for 
setting the pen nibs to rule lines of various thickness is often made 
with its milled head too small. A good arrangement is to have the 



Fig. 24. — Milled Head between the Nibs. 



milled head placed between the nibs of the pen, as in Fig. 24, and 
these are adjusted by right and left-hand threads on the screw of 
which the milled head forms part. Some ruling pens are made 
with the ivory handle to unscrew and serve as a pricker or station 
pointer. This form w^eakens the instrument at the screwed joint, 
and there is little gained in providing in this way a simple 
tool which can, by driving a needle into a pen holder, by any 
draughtsman, be made in five minutes. 





Fig. 25.— How to Set a Ruling Pen. 



Fig. 26.— Point of 
Ruling Pen 
Enlarged. 



The ruling pen is more used than any other drawing instru- 
ment, and occasionally it requires setting or sharpening. This is 
not a very difficult operation after a little practice, yet many 
draughtsmen make a practice of sending their pens to the instru- 
ment makers to be set. By taking out the screw and looking 
directly at the point of the pen, it will be seen that the worn part 
has a flattened surface. If only one nib of the pen has become 
worn shorter than the other, hold the pen upright on the stone 
(fine Turkey or x\rkansas preferred) and grind both nibs level 
before removing the screw and setting. To set the pen place the 
nib on an oilstone in the position shown in Fig. 25. Move the pen 



DBA UGHTSMEN'S INS TR U ME NTS, 



27 



backwards and forwards, at the same time slightly rocking it 
horizontally and vertically. Wipe and examine the pen occa- 
sionally, and stop just short of bringing the point to a sharp 
edge. If the nibs are too sharp, they will cut the paper, and it 
will be necessary to take off the keen edge by using for a few 
minutes on a piece of brown paper. A pen of good hard steel 
will keep its edge for many months without being set. In 
setting the pen, each nib should be brought to a rounded chisel 
edge and both nibs should be of exactly the same length, as 




Fig. 27.— Dotting Pen. 

shown enlarged at Fig. 26, so that when the pen is held upright 
they shall both bear evenly on the paper. 

Dotting pens are used for the purpose of drawing lines com- 
posed of dots and of dashes, the ordinary pattern being such as 
is shown in Fig, 27, where a small roller or rowel is fixed between 
the nibs of the pen. Ink is supplied to this roller which has its 
edge cut to the desired pattern of dots, and imprints them on the 
paper as it is rolled along. Several patterns of dotting wheels or 




Fig. 28.— Dotting Pen with Midrib. 



rollers are usually supplied with the pen, and are stored in the 
cavity shown at the top of the handle, covered by a screwed 
lid. Another pattern, shown in Fig. 28, is provided with 
an internal tongue or midrib coming almost into contact with 
the dotting wheel. It is claimed that with this pen sufficient 
ink can be retained to draw a dotted line 60 feet in length. 
Other descriptions of dotting pen have been produced, some 
being elaborate pieces of mechanism actuating an ordinary pen 
by a cam movement, which derives its motion from a roller 
moved by drawing the instrument along the desired line. It 
is generally admitted by experienced draughtsmen that a 



28 



PRAGTIGAL DRAUGHTSMEN'S WORK. 



dotting pen is an instrument which can easily be dispensed 
with, and it is rarely used by an expert. 

Compasses generally include dividers and pen and pencil 
compasses. The ordinary forms of these instruments are shown 
on p. 23 by the three lower Figs, in the illustration, and need but a 
short reference here. This instrument is for setting off long 
distances and for making large circles. Besides the dividing leg, 
it should be fitted wdth interchangeable legs for pen and pencil, 
and also a lengthening bar, for use when extra large circles are to 
be made. 

Compasses are made with plain points and needle points. 



11 BOLT 



Fi^. 29. 



Fig. 30. Fig. 31. 

Needle Points for Compasses. 



The latter are far preferable, as they do not greatly enlarge 
holes in the paper when drawing a large number of concentric 
circles. Triangular points, which are often found on inferior 
instruments, have a very bad tendency to bore holes in the paper. 
The needle points in Fig. 29 are very good, provided the hole in 
which the point of the needle fits is accurately drilled, so that 
the needle cannot shake, as in this case there is no tightening 
arrangement; a small bolt is pierced at one end by a hole, through 
which the needle passes— a nut on the outer end of the bolt 
enables the needle to be firmly clamped against the leg of the in- 
strument. The screw^ above only prevents the needle from 
slipping backwards, not from shaking sideways. Probably the 
safest needle-holder is that shown at Fig. 30, where the 



DRAUGHTSMEN'S INSTRUMENTS. 29 

hollow holding the needle is split, and tlie needle can be adjusted 
by tightening and loosening the screw. The needle in this point 
can be adjusted so as to project a very little beyond the shoulder, 
which acts as a stop, to prevent the needle penetrating too far into 
the paper. Figs. 31 and 32 show other forms of needle points 
that are sufficiently explained by the illustrations. 

Compass legs are made both with and without a leg joint. Fig. 
18 shows a joint in each leg which is wanting in some instruments. 
These joints are useful, as by their means the point of needle and 
pencil can be kept almost vertical as shown by Fig. 86 on p. 54. 
An unjointed leg forming the centre point of a large circle would 
be very much inclined, and therefore have a tendency to slip, 
at the same time wearing a large hole in the paper. 

Some compasses are so arranged that the legs, after being 
inserted in a socket, are fastened by a screw with a milled head, 
and it is often a source of vexation to find this screw continually 
loosening. A better form of joint is shown in Fig. 33, which 

c-^ ^l ■ ^ g 

Fig. 33. — Socket Fitting for Compass Legs. 

simply depends on an accurate fit and friction to keep the parts 
steady, and if this is well made, it is a much better joint than 
the former. The part marked B (Fig. 33) is a flat piece of steel 
inserted in the circular piece c on the leg, to prevent the 
detachable portion, which is shown in section, from turning 
round. 

To test the joint of a pair of compasses, open them slowly to 
their fullest extent. If they open and close smoothly, without 
unevenness in any part, the joint may be considered to be good, 
but if one part works tightly and another loosely, the compasses 
should be rejected. Another point is to see that the interchange- 
able legs fit accurately, leaving no play whatever. Electrum is the 
'material best suited for their construction, on account of its light- 
ness and freedom from liability to tarnish. The legs should he 
double-jointed ; with these it is possible to keep both points at 
right angles to the paper— a great advantage in good work ; and 
those with needle points should be chosen, as they cause less 
damage to the drawing-paper, and admit of greater accuracy in 
tlieir use. 



30 



PBAGTICAL DBAUGHTSMEN'S WORK. 



Hair dividers are useful for comparing or setting off small 
distances with great accuracy, though with care an equal amount 
of accuracy can be obtained with the ordinary dividers. Hair 
dividers have one leg fitted with a spring, as shown in Fig. 34^ 
with an adjusting screw. The points are first set approximately 
to the desired measurement, and the final adjustment is made by 
turning the milled head of the screw. 




Fig. 34. — Leg of Hair Dividers. 

Proportional compasses are specially for the purposes of reduc- 
tion and enlargement. From Fig. 35 it will be seen that the two 
arms of the compasses are slotted to receive the sliding blocks 
which form the pivot. By means of the milled head shown in the 
figure, this pivot can be clamped in any position in the slots, and 
the relative opening of the two ends of the compasses is regulated 
by the position of this movable centre. A scale engraved on 
one of the arms indicates the position to which the centre 




Fig. 35. — Proportional Compasses. 



pivot is to be set in order to give the required proportion be- 
tween the openings of the two ends of the instrument. Thus, if 
the line engraved on the sliding centre be set to the line figured 3 
on the scale, the opening at one end of the compasses will be 
three times as large as at the other. If the centre is to be set 
1o the line 4, one opening will be four times as large as the other, 
and to enlarge or reduce any measurements on a drawing four 
times, it is only necessary to take the measurements from the 
original drawing with one end of the instrument aiid transfer 
them to the new drawing with the other end. The better 



DRAUGHTSMEN'S INSTRUMENTS. 31 

quality of proportional compasses have additional scales 
engraved upon them, giving the ratios of diameters of circles, 
areas, and other tables, and some have also a rack and pinion 
motion, for setting the centre pivot in its correct position. 



Fig. 36. — Bow Corr.pass. 

Bisecting compasses are a simple form of proportional com- 
passes, intended for measuring and setting off lengths only in 
the proportion of 1 to 2. They are, accordingly, provided with a 
fixed pivot, and have no means of adjustment. 




Fig. 37. — Spring Bow Dividers. 




Fig. 38. — Spring Bow Poncil. 




39.— Spring Bow Pen. 



Bows (Fig. 36) are used for describing smaller circles, and these 
may be obtained also either single or double jointed, or with 
plain or needle points. Double-jointed bows, with needle points, 
arc well worth the extra cost. 

Spring bows are used for making small circles. They are sold 



32 



PRACTICAL DRAUGHTSMEN'S WORK. 



in sets of three, comprising dividers, pen bow and pencil bow. A 
set is illustrated by Figs. 37, 38, and 39. 

A form of spring bow which is known as the " pump " pen is 
shown in Fig. 40. In this, one leg consists of a straight rod about 
4 in. long. The pen or pencil forms the other leg, which revolves 
freely around the centre rod. The method of using is shown at 
Fig. 122, p. 69. The pen and pencil points are interchangeable, and 
a larger circle can be described with this instrument than with the 





Fig. 40.— Pump Bows. 



Fig. 41. — Spring Bows. 



ordinary spring bows. Fig. 41 shows another form of spring bow 
with which larger circles can be drawn. 

Beam compasses are useful for striking very large circles. 
Those fitted with a socket to take a lath are the cheapest, and are 
suitable for all practical purposes. It is advisable to have one 
end fitted with a screw adjustment, as this saves a lot of trouble 
in setting to the required radius. 

Beam compasses are somewhat costly, though not difficult to 
make. The home made beam compasses about to be described 
are generally used in preference to the superior and ortho- 
dox kind, principally on account of their great lightness. 
The beam was made from an old boxwood 18-in. scale 
that was badly damaged on one edge. This was ripped 



DRAUGHTSMEN'S INSTRUMENTS, 



33 



down the middle and trued up; the scale on the upper 
edge afterwards proved to be of great use in adjusting the two 
points. 

Having made the beam, cut two strips of tin about fin. or fin. 
wide, and long enough to go round the beam, and make a lap-joint 
as shown in Fig. 43 and also in all the other figures ; bend these 
strips tight round the beam, so that they will just slip, and solder 
the lap-joint. From two other strips of tin bend up two split 
tubes, one as in Fig. 42, to fit a drawing pen, the other to fit a 





Fig. 42. 



42.— Pen Point. Fig, 
Back of Holder. Fig. 
Section through Beim. 
45. — Needle Point. 

BEAM COMPASSES. 



43.-» 
44.— 

Fig. 



Fig. 45. 



short piece of ordinary wooden penholder. These split tubes 
should be soldered to the two tin straps, on their plain sides, in 
the positions shown in Figs. 42, 43, and 45. 

The piece of wooden penholder that fits the other split tube, 
and forms the needle-point, should be about the same length as 
the drawing-pen. Into one end of it drive part of an ordinary 
fine sewing needle, point outwards, then shape the penholder 
as a pencil is sharpened (see Fig. 45), and the needle-point is 
complete. When not in use it is well to keep a bit of cork stuck 
on the end of the needle-point for protection. When fixing 
together for use, as in Figs. 42 and 45, the pen and needle-point 
should be kept perpendicular, and in the right position. Should 
the straps and split tubes at any time work a little loose, they can 
easily be tightened by a slight pinch with the thumb and finger. 



34 



PEAGTIGAL DBAUGETSMEITS WORK. 



Should a pencil-point be wanted instead of a drawing-pen, it is 
easy to get one to fit well into the split tube made for the pen. 

A cheap makeshift beam compass, with which good work can 
be done, may be made out of a blind lath and two good-sized 




Fig. 46. — Cheap Beam Compass. 

corks, such as are used in pickle bottles. Holes for the reception 
of the lath and drawing pen, and also for the pricker or needle 
stuck into a penholder, are burnt and cut through the corks as 




Curve Bow. 



shown in Fig. 46. The cork takes a good grip of the lath, and 
the instrument is quite steady and pleasant to work with. 

For very flat curves, a Carve Bow (Fig. 47) is sometimes 
used. It consists of two wooden beams, one being a rigid piece 
of hard wood with a screw working through the centre ; the 
other a thin, pliable strip, which is bent by the turning of the 
screw. Within narrow limits, this instrument can be adjusted to 
varying radii, but if the strip be bent beyond a moderate extent 
the curve loses its circular character and becomes approximately 
parabolic. 

For inking-in large curves, such as those of elliptical arches, 
"splines" are very useful. These may be made of lancewood, 



DRAUGHTSMEN'S INSTRUMENTS , 35 

hickory, or ash, about J in. square. They are bent to the required 
curve, and kept in position by means of weights. 

Eailway curves (Fig. 48) may be obtained in cardboard, pear- 




Fig. 48. — Eailway Curve. 

wood, or ebonite, with radii varying from 1^ in. to 240 in., each 
curve being numbered according to its radius in inches. These 
are also useful for setting out flat curves, such as those of camber 




Fig. 49. — French Curve, 

arches and the lines of railway sidings. 

When curves of ever- varying radius are to be inked in, the 
French curve, shown in Figs. 49 to 51, is used, This consists 




Fig. 60. — French Curve. 

of a flat piece of hard wood cut out into more or less intricate 
patterns, with almost any curve between a straight line and a 
very small circle. When inking in a curve on the drawing with 
the curve, it is necessary to find some portion of the >vood which 



36 FRACTIGAL DRAUGHTSMEN'S WORK. 

exactly coincides with a certain part in the drawing ; this should 
be inked in with the pen, the curve should be removed, and 
some other portion of it found to continue the curve from the last 
point. This process is shown in Fig. 134, p. 77. French curves are 
made in pearwood, in a great variety of shapes. Figs. 49, 50, and 
51 show useful patterns, and a few of these in varying sizes will 
be sufficient for most purposes. 

In cases where there is much repetition of a complicated 
detail in drawing, it is a saving of time to make suitable tem- 
plates out of soft wood, with which the outlines can be rapidly 




Fig. 51. — French Curve. 

drawn by passing the drawing pen round them. Small templates 
can be shaped with a penknife, the curved portions being 
smoothed with a file and glasspaper. 

In addition to the curves enumerated above, the draughtsman 
should provide himself with a few thin pieces of pearwood or 
mahogany, from which a template to suit any required sweep 
may be easily made with the penknife and a piece of glasspaper. 

Jt should be remembered that a draughtsman who can strike 
in his curves with a steady freehand sweep often saves himself 
much piecing up of odd lengths of curves selected from the 
template, and is certain to obtain a more harmonious effect in 
the end. 

The methods of using draughtsmen's instruments will be eii- 
plained in the following chapters as opportunities otfev, 



37 



CHAPTER III. 

DRAWING STRAIGHT LINES. 

It is presumed that the reader has procured a selection of the 
instruments already described, and that he is now desirous to 
attain skill in using them. 

This course, outlined in this and the following chapter, 
while simple enough for youths yet at school, will be found 
equally suitable for adults who desire to make accurate working 
drawings, and who have had no preliminary training, and 



Fig. 




Method of Holding T-square. 



for young professional draughtsmen who have not learnt the 
basis upon which their art depends ; it will also lead up to the 
drawing required by the Department of Science and Art in the 
subjects of machine and building construction. 

To commence the practical work of making a drawing, set the 
drawing board on a fiat table, and raise the back edge so that a 
sloping surface is presented to work upon. Place the paper about 
half an inch from the left-hand and bottom edges of the board, 
with the smooth side uppermost, and fix a drawing pin in the 
top left-hand corner of the paper, put in square and pressed 
firmly down. Now take the T-square, holding it as shown in 
Fig. 52, and slide it up to the top edge of the paper, swinging the 
paper upon the pin already put in until it coincides with the 
upper edge of the T-square ; then put a second pin in the 



38 PEAGTIGAL DRAUGHTSMEN'S WORK, 

bottom right-hand corner, and afterwards in the two remaining 

corners. 

The pencil should be used solely at first for practising, 
and the most expensive drawing pencils are often the most 
economical to use in the drawing office. There are many well- 
known makes that may be depended upon to work smoothly 
and evenly without grittiness or inequality of texture. The 
number of H's marked upon the pencil indicate its relative hard- 
ness. For general use those marked H or HH will be suitable, 
while for particularly fine work HHHHHH may be necessary. 
For roughly sketching details on a large scale, a very soft lead, 
such as B will be found pleasantest to work with. Pencils 
of unvarnished cedar are to be preferred, and those of a 




Fig. 53.— Chisel Shaped Fig. 54.— Round Point to 

Pencil Point. Pencil. 

hexagonal section do not roll off the sloping surface of the 
drawing-board or desk. 

In sharpening the pencil a chisel point (Fig. 53), not a round 
point (Fig. 54), should be produced. Almost the first lesson for a 
draughtsman is how to properly sharpen a pencil, which is not easy 
for the beginner to accomplish satisfactorily. A pencil point 
should be well sharpened so that when the pencil is passing along 
the edge of a square it should be closely against it ; and in 
ordinary drawing or tracing, a clear view should be obtained 
completely around it on the paper. 

A round point wears away very rapidly, and will hardly make 
even one fine line, whereas if the edge be kept the full thickness 
of the lead in the direction of the line the pencil will last very 
much longer and produce better work ; the fiat faces of the lead 
point may be slightly rounded, as shown by Fig. 53. 

If properly sharpened, one operation of the knife on the wood 
will be sufficient to allow of several re-sharpenings of the lead, 
whilst a badly sharpened point requires further hacking of the 
wood every time the lead is slightly worn. 

Fi^. 55 shows the T-square and pencil with the two hands in 
position for drawing an ordinary horizontal line. The pencil 



DRAWING STRAIGHT LINES. 39 

should be upright when looking m the lengthways direction of 
the line, and sloping about five degrees from the upright in the 
direction in which it is being drawn, as would be seen at right 
angles to the line. 

Now from each edge of the paper mark off f in. and draw a 
border line all round, with plain square corners. The three 




Fig. 55.— Method of Holding Pencil. 

fingers at the back of the stock of the T-square keep it close to 
the edge of the board, which is not easy to do at first starting, 
but with a little patience and perseverance every border line can 
be drawn with equal facility. It is important to note that all 
pencil lines upon a drawing should be thin ; if made thick they 
cannot be inked over so neatly, and the paper will have a greasy 



■-^tA — 



Fig. 56. — Line in Error. Fig. 57.— Dotted Line. 

feel to the pen. The indiarubber should be used very sparingly, 
and if possible only after a drawing is completely inked in. 

A pencil line drawn in error should have a wavy mark across 
it (as in Fig. 56), and one drawn full, but intended to be inked in 
dotted, should be marked as in Fig. 57 : this is instead of rubbing 
them out at the time. Another fundamental principle is always 
to draw a line far enough at the first attempt, but not to draw it 
beyond the distance it is known to be wanted. An unnecessary 
line takes time to draw, wastes the pencil point, and takes time to 
rub out ; all matters of moment when excellence is in view. 

The draughtsman will, at the onset, find it interesting and 
useful to test some of the instruments as to their essential 
qualities. For instance, a straightedge to be of use must be 
truly straight ; the working edge of a T-square is a straightedge, 
and this may be tested by drawing with a fine chisel-shaped 
pencil-point a line as long as possible against the working edge 
of the T-square ; then turn the blade over, and, setting the ends 
carefully to the line just drawn, draw another line against the 



40 



PRACTICAL BEAVGIIT8MEWS WORK 



same edge adjacent to the line previously drawn. The principle 
of this test is shown in Fig, 58, where it will be seen that any- 
irregular ity in the edge is doubled in magnitude by the pencil 
lines. If the lines coincide exactly throughout their length, the 
edge is true ; if they do not, the edge must be trued with a 




■Testing' Straightedge. 



fine-set plane, or glasspaper wrapped round a flat piece of wood. 
The stock of the square should be exactly at right angles with 
the blade, but, as usually constructed, this is rather difficult to 
test without some true instrument of reference ; and, paradoxical 
as it may seem, it does not matter if the stock is not exactly at 




I jt.J'L - 



Fig. 59. — Untrue T-square makes Correct Angles. 



right angles, as will be seen by Fig. 59, where, of course, the 
divergency is greatly exaggerated. In fact, the squareness of 
the T-square is entirely unessential for any work, but the absolute 
squareness of the board is most important. It will be observed 
that if the paper be set by the T-square, all lines drawn upon it 



DRAWING STRAIGHT LINES. 



41 



by an untrue square will still be parallel and perpendicular, so 
that a true drawing will be produced. If, however, the board be 
not square, a true T-square will not enable a square drawing to 
be made, as wull be seen by Fig. 60, where the T-square is correct 
but the drawdng-board is not square, causing the intended hori- 
zontal and vertical lines drawm upon it to have an angular error 
the same as the board. 

The set- squares may next be tested. The end-grain edge and 
the long edge may be tested and trued up in the same way as the 
edge of the T-square blade ; then, to test the right angle or square 




Fif?. 60. — Untrue Boari makes Incorrect Angles. 



corner, hold the T-square firmly on the board, as shown in 
Fig. 61, and with the set-square against the top edge draw lines 
a 6, a c, wdiich will coincide if the squares are true, or may show 
any of the errors depicted in Fig. 61. This edge should then be 
trued up until the lines drawn upon reversing the set-square 
truly coincide. To straighten the edges of a set- square, lay a 
sheet of fine glasspaper on a level surface, place a wood block b 
with a square edge (see Fig. 62) on the paper, put the square s 
against the block, and rub the edge on the glasspaper until the 
angles are correct and the edges straight. The edges when very 
faulty may be planed with an iron snioothing-plane, and after- 
wards finished with glasspaper as described above. It is well to 
note that large set-squares produce better work than small ones, 
although the latter are more often used on account of their 
portability. 



42 PBAGTICAL DRAUGHTSMEN'S WORK 

Now to test the drawing-board, and more particularly the 
working edges, which are the left-hand and bottom edges. There 
is one point in making a drawing-board that the inexperienced 
sometimes lose sight of, and that is the necessity of making the 
board perfectly rectangular. If this be done, the T-square may 
be shifted from one edge to an adjacent one, and lines drawn 
from the new position of the square will be at right angles to 
those drawn from the first position, although, as just explained, 
the T-square may be very far from square itself. First try the 
trued edge of the T-square along the edges of the board to see 
that they are neither hollow nor rounding, then rule a vertical 
line from the bottom edge, and, placing the T-square horizontal, 



eUb 






a a a 



Fig. 61. — Testing- Set-square. 

draw a vertical line by means of the set-square, which should 
coincide with the vertical line previously drawn by the T-square ; 
if it does not, the lower edge of the board should be shot, that is, 
planed true, afresh, and tried until the test shows no error. The 
board, T-square, and set-squares may now be considered to be in 
good working order and ready for use. 

Before leaving this part of the subject, it may be useful to 
point out how parallel and perpendicular lines may be drawn 
when they are not in the same direction as the edges of the 
board. Fig. 63 shows the ordinary method used by draughts- 
men ; one set-square being laid down on the paper, the other is 
placed against it so that its long edge slides against the long 
edge of the former, and the two free edges give parallel and 
perpendicular lines as required. The carpenter and joiner may 
do this more readily with a stifF-jointed 2 -ft. rule, using the 
drawing-board and T-square as shown in Fig. 64. 



DRAWING 8TRAIGET LINES. 



43 



Tlie testing and adjusting of the drawing-board, T>square, and 
set-squares having been satisfactorily accomplished, the draughts- 
man may now test and adjust himself so that he may be able to 
do his own personal work with the same relative precision. 




Fig. 62.— Straightening the Edge of a Set-square. 



























'^ 






N 
\ 
\ 


C' • 








K 










/. 


\ 


1 


1 


X 





Fig. 63. — Drawing Parallel and Perpendicular Lines by Set-squared. 

Draw upon the paper a firm T, as in Fig. 65, each of the two 
lines being exactly 2 in. long. Now study it attentively from a 
distance ; at first the vertical stroke will seem much longer than 
the horizontal one, but by comparing the parts carefully it will 
be seen that the first impression was not a true one. Now, with 
one edge of a set-square, draw a straight line as nearly horizontal 



44 



PEAGTIGAL DRAUGHTSMEN'S WORK 



as can be judged by the eye only, and 2 in. long. Mark what is 
judged to be the centre of its length, and then draw another line 




Fig. 64.— Drawing Parallel and Perpendicular Lines with T-square 
and 2-ft. Rule. 



Fig. 65. — Equal Horizontal and Vertical Lines Appear Unequal. 

of tlie same length at what is estimated to be a right angle from 
it. Test all these points oy T-square and measurement, and 



DRAWING STRAIGHT LINES. 



45 



practise similar examples of jiadging lengths, central points, and 
angles, till the judgment will bear the test of measurement. 

In the next example, Fig. 66, it requires some little practice 
to detect the true relative position of the three white spots, as the 
eye is easily deceived. In the drawdng the white dots are 




Fig. 66. — Equal Spaced Spots Appear Unequal. 

uniformly spaced, but, to most people, the distance on the right- 
hand space looks much longer than that on the left, solely by 
reason of the lines drawn angleways confusing the judgment. 
Again, in Fig. 67, the two inner horizontal lines crossing the 
inclined ones are exactly straight and parallel with each other, 
but to many persons they look curved and wider apart in the 



^<^>x\ /y^^^ 




'^^^^^<^X / X'^^v^^^^S^ 



Fig. 67. — Two Parallel Straight Lines Appear Curved. 

centre. This same principle is shown more strikingly in Fig. 6% 
where the vertical lines are all truly parallel, although they look 
to be alternately converging and diverging. 

In Fig. 69 a true square is first drawn, and when part of the 
lower half is covered, it looks as if much more than the covered 
part is missing. In Figs. 70 and 71 the two circles are precisely 
the same size, but the black on a w4iite ground looks smaller 
than the white on a black ground. This appearance is caused 



46 



PRACTICAL DRAUGHTSMEN'S WORK. 



because the white surface reflects the light, while the dark 
surface absorbs it. 

A curious test for the eyesight is shown by Fig. 72, which 
consists of two black dots, about J in. diameter, printed upon the 




Fig*. 68. — Parallel Lines Appear to Converge and to Diverge. 




Fig. 69.— Square Partly CovereJ. 



paper at a distance of 3 in. centre to centre. Shut the right eye, 
and, with the left eye, look at the right-hand dot ; on moving the 
paper nearer or farther there will be found one position, when 
the eye is about 9 in. from the paper, at which the left-hand dot 
vanishes ; at all other positions both dots can be seen at the 



DB AWING STRAIGHT LIJSfES. 



47 



same time, although the eye is directed to the right-hand one 
only. This is owing to a small part of the retina of the eye 
having no power of vision, called the " blind spot," and it is 
why sometimes, the head being held in a certain position, a 
dimension figure w^ill disappear from a drawing. On the other 





Fig. 70. Fig. 71. 

Figs. 70 and 71. — Circles of Equal Size Appear Unequal. 

hand, the eyes can sometimes see more than one would expect, as 
when a stereoscopic view is held in the hand and gradually 
brought into position until the two pictures appear superposed, 
when the vista of true perspective will give an air of solidity to 
the view equal to any stereoscope. Composite photographs may 
be optically produced in this way from two separate cards of 



Fig. 72. — Disappearing Dot Illustrating Blind Spot in the Eye. 

persons, showing the heads about the same size and position, 
Not only upon the drawing-board and in the workshop should 
the eye be educated ; the same kind of practice should be kept 
up out-of-doors and in the workshop. 

The set of examples illustrated by Figs. 73 to 75 may be 
tried over again when the lines are closer together, when any 
irregularities will be found to show much more clearly. If the 



48 



PRACTICAL DRAUGHTSMEN'S WORK, 



lines are placed less than y^ ^^' apart, they will appear, at a little 
distance, like an even tint of shading, and the closer they are the 
more difficult will it be to get the appearance quite uniform, but 
this is very good practice. 

The following examples (Figs. 73 to 75) are selected out of a 
large number of possible combinations, as giving variety of prac- 
tice while not appearing too difficult. They are, however, more 
difficult than they appear, so that they must be commenced with 
the determination to produce very neat and accurate drawings. 

After dra*wing the border line in pencil, f in. from each edge 





D 




4^ 


/ 










\/ 





Fig. 73. Fig. 74. Fig. 75. 

Figs. 73 to 75. — Square Figures for Practics in Drawing. 

of the paper, as already described, find by measurement the 
centre of the paper, so that the second square (Fig. 74) may be 
placed in the middle, rule a horizontal line for the squares to 
rest upon, draw the middle one in outh'ne first, and then the 
others, each measuring 3 in. along one side. The spaces between 
the border line and each of the squares should be equal. In the 
upper half of the first square (Fig. 73) mark off equal divisions of 
i in. each, and draw horizontal lines ; then, in the lower half, 
mark off similar distances and draw vertical lines. In the second 
square (Fig. 74) equal distances must be set off from each of the 
sides, and parallel lines drawn, so as to make a number of com- 
plete squares. These should be drawn with a fine chisel-pointed 
pencil, and then tested by drawing diagonal lines from opposite 
corners. If the squares have been correctly set out, all the angles 
will be upon one or other of the diagonal lines. In the third 
square (Fig. 75) the inner squares are drawn with their angles 
tangent to the sides of the one next larger. If very fine pencil 
lines are drawn across opposite angles of the outer square, and 
then two other lines bisecting the sides, it will be found easy 
%o join up the inner squares to the points so found. 



DRAWING STBAIGHT LINES. 49 

The next lesson illustrates the method of drawing and inking 
lines. A border line may be pencilled round the paper fin. 
from each edge; then rule horizontal lines, the top one being 
about 2 in. below the top border line. About 1 in. below, 
mark the position for the upper full line, and from this mark 
off five more positions each Jin. distant from that above it. 



Fig. 76.— Full Lines. 

Then, through the two first positions, draw full lines (Fig. 76), 
9 in. long and with each end equidistant from the border. 
Through the ends draw faint lines vertically downward, and then 
draw the dotted lines (Fig. 77) and dimension lines (Fig. 78), 
their lengths being limited by the faint lines just mentioned. 
Dotted lines, as shown in Fig. 77, are used to represent hidden 
edges of surfaces ; they are sometimes called broken lines, and 



Fig. 77.— Dotted Lines. 

consist of alternate short strokes and spaces measuring about 
Y^6 in. each. Dimension lines, as shown in Fig. 78, consist of open 
dotted lines. These dimension lines are to guide the eye from 
arrow-head to arrow-head in reading dimensions, as shown in 
Fig. 79 ; they should consist of strokes not more than Yt^^- long, 
and not less than J in. apart ; in long dimension lines the strokes 
may be 4 ii^- apart. It will be worth while to measure these 



Fig. 78. — Dimension Lines. 

distances the first time of drawing them, but a very little practice 
should enable a draughtsman to judge of the correct length with- 
out actual measurement. When making finished drawings, in 
practice it is found best, when inking in, to use straight blue 
ink lines terminated at the ends by black arrow-heads. 

When it is desired to show the interior construction of any 
object, an imaginary cut is made through it, and the representa- 

D 



50 FRAG TIG AL DRAUGHTSMEN'S WORK. 

tion of the cut surface is called a section. The direction of the 
cut is marked upon the original drawing by a line of section, 
formed of strokes and dots placed alternately, with a letter at 
each end, as a b upon Fig. 80. This line is usually in red ink, 

Fig. 79. — Method of Showing Dimensions. 

but as all the work in the present lessons is black and white this 
dotted section line may be made the same as the other lines. 
The horizontal graduated lines in Fig. 81 are meant to be of 
different thicknesses ; this is done when inking-in ; for the present 
simply draw five thin pencil lines 4 in. apart. 



Fig. 80.— Line of Section. 

Before beginning to ink-in the figures that have been pencilled, 
see that the drawing-pen is clean. Never let the ink dry between 
the nibs, but wipe the drawing-pens with a piece of soft rag after 
using. In inking-in always try to improve upon the pencilling, 
get an exact fit at all angles, and let tangent parts just touch — 
neither more nor less. 



Fig. 81. — Graduated Lines. 

The next process is to ink-in the straight lines. Take the draw- 
ing-pen (Fig. 19, p. 24), open it about a sixteenth of an inch, then 
clo.se It by the screw until daylight just shows between the nibs ; 
now hold it in the lips, and breathe between the nibs, then dip them 
carefully into the Indian -ink bottle so as just to touch the surface 
of the liquid, when the ink will run up between the nibs, follow- 
ing the moisture deposited by the breath without wetting the 
outside of the pen. Try on a separate piece of paper for the right 
thickness of line. A piece of chamois leather or rag should be 



DRAWING STRAIGHT LINES, 



51 



kept handy to wipe the outsides of the nibs in case of ink being 
there, because if ink be allowed to get on the outside of the pen, 
a blotted line will be the consequence. 

Now hold the drawing - pen as shown in Fig. 82 and 
carefully ink-in all the horizontal lines, both full and dotted, 
correcting, if possible, any slight irregularities that may have 
been made in pencilling. In drawing the graduated lines 




Fig. 8!{.— How to Hold a Ruling Pen. 



Fig. 81), begin with the thinnest, then with the middle finger, as 
shown in Fig. 82, turn the screw of the pen back, say, about a 
quarter of a revolution for each of the others, the last opening 
being about the right thickness for the border line. As the 
border line takes longer to dry it is very easy to smear, but of 
course this may be avoided by letting the ink dry while prepar- 
ing the ink-leg for the compasses. 



52 



CHAPTER IV. 

DRAWING CIRCULAR LINES. 

Compass curves is the name given to all curves composed of 
circular arcs. Thej can be drawn by the compasses in one or 
more operations, and the name distinguishes them from lines 
of varying curvature, which are again divided into various classes 
according to their character. With compasses in hand, the con- 




Concentric Circles. 



struction of a circle is so simple that anyone can strike a circle 
of some sort ; but many persons who think they are draughtsmen 
cannot draw a good circle. Strike, describe, and draw are three 
terms used indiflerently for the operation of maHng a circle. 

To ensure good work : Hold the compasses by the top joint ; 
place the pencil or pen perpendicular to the paper and, sloping 
it slightly in the direction of motion, make the circle by one 
sweep of the compass. Now try to make three concentric circles, 
as shown at Fig. 83, on the paper by these rules, remembering 



DRAWING GIEGULAE LINES. 53 

that concentric circles are those having the same centre, and 
proceeding as follows : — 

As when drawing straight lines, first commence with a border 
line, three-quarters of an inch from the edge all round the paper, 
then draw vertical and horizontal centre lines, so that their 
intersection will show the point where the point of the com- 
passes is to be placed. Open the compasses to 2 in., measured 
on one of the scales, and strike the outer circle. Then partially 
close the compasses to l|in. on the scale, using only the right 
hand for the compasses and the left to steady the scale, and 
describe the second circle. Then close further to 1 in. and draw 




Fig. 84.— Finding Centre of Circle. 

the inner circle. The illustrations printed in this book are half 
the size they are to be drawn. 

The difficulty of estimating the point that is exactly the 
centre'of a circle may be tested by taking a penny and marking the 
outline of a circle with it on the paper ; then mark where the 
centre is estimated to be, and afterwards test it by drawing short 
arcs from four opposite points by the compasses, as in Fig. 84. 
Following this, a useful practice would be to sketch a circle 
freehand and test it by finding the mean centre, and then striking 
a true circle by the compasses. 

As a further lesson, the interesting work of drawing curves may 
be taken. The curves across the lower part of the diagram (Fig. 
85, p. 54) are known as flat curves, because, having a large radius, 
they have not very much " bend " in them. To draw these, first 
put in a thin centre line down the paper, then mark the positions 



54 



PRACTICAL DRAUGHTSMEN'S WORK. 



where the curves cross the centre line 4 in. apart, and from the 
inner one measure 6 in. to point (Fig. 85), which is to be used 
as the centre. Open the compasses wide enough to make the 
largest curve first ; see that the point of the compass pencil is 
chisel-shaped, as shown in Fig. 53, p. 38, and in the right direction 
to make a thin line ; if the compass leg has a joint, bend it so that 




Flat Curves* 



the pencil is at right angles to the paper, and then, holding the 
compasses by the top, as in Fig. 86, swing them round carefully 
to make the curve the required length. Do the same with the 
other two curves in Fig. 85, putting the dotted one in as a full 





Fig. 86. — Holding Compasses, 



Fig. 87. — Sharp Curves. 



line, and making a few short strokes across it, as shown in Fig. 57, 
p. 39, to indicate that it must be dotted when inking-in, as de- 
scribed on p. 39. 

Large or fiat curves are really more difficult to draw than 
small ones, although many think the contrary, but the fact is 
that any irregularity shows more in a small curve. Now very 
carefully mark the centre (Fig. 87), and measure off i in. distances 
along a thin horizontal line through which the small curves will 
be drawn, the largest of them being 3 in. radius. This completes 
the pencilling ; but, to ensure neat work in inking, see that the 
terminations of all the lines and curves are clearly indicated, 



DRAWING OIRCnLAB LINIES. S5 

either by a thin pencil line drawn across their ends, or by being 
drawn very neatly and terminated evenly. 

Next try some pieces of circles, or arcs, as they are called. 
Let them be concentric, as shown at Fig. 88, with radii of 3 in., 
3jin« and 4 in., and each 4 in. long, measuring from end to end 




Fig. 88. — Concentric Arcs. 

in a straight line, that is, measuring the chord of the arc instead 
of the arc itself. These might be called parallel curves, and, 
although this is an expressive term and not likely to be mis- 
understood, they are not a correct example of parallelism. 

, Now try three more arcs, but all struck with the same radius, 




Fig. 89.— -Arcs of Equal Kadius. 

as at Fig. 89, say 3 in., and the same distance apart on the centre 
line, say i in. These curves are exact counterparts of each other, 
although they look much less regular than the concentric arcs, 
and an important principle is involved in the comparison. 

To find the centre of any small compass curve as a b. Fig. 90, p. 
56, from points A and b strike arcs of the same radius intersecting 
at c and d, and draw a line through the intersections cutting the 
arc at e. This line will pass through the centre. Then from 
points e and b, with a rather smaller radius, strike arcs inter- 
secting at / and (/ ; draw a line through these intersections, and 



56 



PRACTICAL DRAUGHTSMEN'S WORK 



^vliere it cuts the previous line will be tlie required centre, as 
sliown at h. 

Before drawing the circles (Figs. 91 to 93), a pair of centre 




Fig. 90.— To Find the Centre of a Small Arc. 

lines cutting each other at right angles must be drawn for each, 
and it should be a stringent rule never to draw a circle under any 
circumstances without first having two centre lines to mark its 
position. In the first circle (Fig. 91), mark off points J in. apart 






Fig. 91. Fig. 92. Fig. 

Figs. 91 to 93.— Circles for Practice. 



93. 



along one of the diameters from the circumference to the centre, 
and then describe the concentric circles with the comi)asses, 
taking care not to bore a large hole through the paper with the 
point. The compasses, if properly sharpened, should barely pene- 
trate the paper and leave no impression on the board. 

To fill up the middle circle (Fig. 92), set the compasses to the 
radius, and then, putting the point at the intersection of one of 



DRAWING C TEGULAR LINES, 



57 



the centre lines with the circumference, mark across the circum- 
ference on each side ; do the same at each intersection of the 
centre line with circumference, and it will be found that the 
circumference is then divided into twelve equal parts. Now join 
each opposite joint by a line passing through the centre and the 
figure will be complete. 

The last figure to be drawn (Fig. 93, p. 56) is the most difl[icult, but 
has the best effect, so it is worth taking some pains over. Draw 
the two centre lines, put in the large circle, and divide the hori- 
zontal diameter into Jin. spaces. Take the bow-pencil (Fig. 38, p. 31) 
or small compass (Fig. 36, p. 31), set it to ^ in. radius, and then put in 




Fig, 94. — Old-fashioned Hollow Edge of CastingSi 



the smallest semicircle on each side. Then set it to J in. radius, 
and put in the next semicircle ; then to fin. radius for the next 
two semicircles, which should exactly meet at the centre. Now 
to 1 in. radius, and, lastly, to 1 J in. radius, checking the curves 
before actually drawing them, by seeing how they fit with those 
already drawn. 

Curves applied to machinery and buildings, as a rule are 
introduced with an object in view. A favourite method of 
finishing the edges of castings, until about thirty years ago, was 
to run a hollow curve along them as in the illustration. Fig. 94. 
This is very easily drawn by opening the compasses to the 
required radius and placing the point at the junction of the two 



58 



PEAGTIGAL DRAUGHTSMEN'S WGEK 



straight lines, as seen in the section. When engineers began to 
consider the why and the wherefore, and to see beauty only in 
that which was strictly adapted to strength or economy, they 
saw that this curve was even worse than a plain angle, for it gives 
two sharp edges to damage and be damaged, and a groove to hold 
the dirt. 

A rounded angle (Fig. 95), whether internal or external, was 
found to produce a better arrangement of the crystallisation of 
the iron in cooling, it gave a stronger casting, was less liable to 
damage, and altogether more appropriate. This is perhaps 




Fig. 95. — ^IModem Angle of Castings Internal and External. 



the most important curve a beginner can have ; though difficult 
to draw well if the centre has to be guessed at, it presents no 
difficulty and takes less time if the right method be followed. 
First decide upon the radius, say 2 in. ; set the compasses to this, 
place the point at the intersection of the straight lines a, and 
mark with the compasses across each of the lines b and c. Then 
from the intersections of each of these marks, draw intersecting 
arcs within the lines to give the exact place, marked d, for the 
point of the compasses to draw the rounded angle. If care be 
taken it will be found that the curve exactly fits the straight 
lines, which is of course what the draughtsman should aim at. 

A more advanced example, such as would occur in fitting a 
curve between the arm and boss of wheel, is shown at Fig. 96 



DRAWING CIRCULAR LINES, 



59 



Let a be the centre of the wheel, a h the radius of the boss, say 
3 in., and h cd part of the boss ; also let c? 6 be part of the arm. 
It is required to join them by a curve of li in. radius. Open the 
compasses 1| in., and from two points on the curve, and two on 










/ 



/ 



7,J 



"l 



/I 
/ • 



Fig. 96. — Curves Joining Arms and Boss of Wheel. 

the straight line, draw short arcs as shown at f g, h i. Then 
draw a straight line tangent to the two arcs from the line, and 
with the compasses a concentric arc tangent to the two small 
arcs from the curve. Where this new line and curve cross each 
other {j) will be the exact centre for the curve of 1^ in. radius to 



60 PRACTICAL DRAUGHTSMEN'S WORK, 

.join the arm and the boss. It is important to note that the exact 
point of meeting of the two curves will be at c in the line aj^ 
joining their centres ; and of the curve and straight line at k^ 
where a perpendicular would fall from^. 

The illustrations given in Figs. 94 to 96, pp. 57—59, show 
the application of the simplest elements of practical geometry to 
the production of good junctions in the outlines of a drawing. 




Fig. 97. — Example Eequiring Accurate Drawing. 

The study of practical geometry forms a very good ground- 
work for a draughtsman, and in machine drawing is quite indis- 
pensable ; but for architectural drawing there is a great deal that 
may be omitted. One of the advantages pertaining to it is that 
it compels neat work, as the problems will not work out unless 
accurately set off. 

The illustration shown at Fig. 97 is left without any explana- 
tion ; it will be found interesting to work out, and it will also be 
a good example for showing accurate draughtsmanship. 

Fig. 95, p. 58, shows how a square angle is rounded off with a 
given radius. After considerable practice the draughtsman can often 
guess the position of the centre of the curve fairly accurately, but 
instead of prodding about to find a centre which will permit the 
curve to meet the straight lines, it is better to use the geometrical 
method, which is as follows ; Produce the two lines till they meet 
at A as shown dotted ; then, with the meeting point a as centre and 
a radius equal to the radius of the required curve, cut each of the 
two lines at B and c, and, from each of these two points as centres, 
strike arcs that cut one another at d, which is the required centre. 



DRAWING CIRGULAE LINES. 



61 



The tangent curve can then be drawn accurately and easily. With a 
little practice, this method is so much more rapid and exact than 
guessing at the centre that there is good reason for adopting it 
always. Fig. 94, p. 57, is the opposite of Fig. 95, and is too simple 
to need explanation. 




Fig. 98. — Rounded Corners. 



Fig. 99. — Parallel Lines joined 
by a Semicircle. 



Fig. 98 shows the method just described applied to three 
straight lines forming two right ang es and having two adjacent 
corners rounded. 

Fig. 99 shows how to deal with two parallel lines that are to 
be joined tangentially by a semicircle. In this case bisect the 
space between the two lines by a perpendicular line that must 
contain the centre of the circle from which the required curve is 





Fig. 100. — Angular Lines Joined by Circular Arcs. 



formed. Determine the extreme position of the curve and mark 
from it, along the centre line, a distance equal to half the distance 
between the lines, and this mark will be the centre of the required 
circle. 

Fig. 100 is more difficult, as in this figure the lines, which it is 
desired to join by a curve, are not at right angles. Therefore, 
inside these, and at a distance from them equal to the radius of 
the curve which it is desired to use, draw two parallel lines. To 



62 



PEAGTIGAL BE AUGHT SMEWS WORK. 



do this, take the radius in the compasses and strike two arcs at 
some distance apart along the inside of each line. Tangent to 
these draw the two inner straight lines shown dotted, and their 
intersection will give the centre required. The exact points of 
i unction of the straight lines with the curve can be found by 
drawing perpendiculars from the centre to the straight lines by 
the method shown on the left-hand side of Fig. 100. 

The figure on the left side is exactly similar to the last, with 
the exception that it represents a sharper angle than that shown 
by the angle or corner in the right hand figure. 

Fig. 101 shows the junction of a straight line and curve by a 




-<- • I 





Fig. 101. Fig. 102. Fig. 103. 

Figs. 101 to 103. — Examples of Curved Lines as Junctions. 

smaller curve. In this example, after drawing the given straight 
line and circle, set the compasses to the required radius, and from 
any point on the circumference of the circle describe a short arc 
outside it. From the centre of the circle draw a straight line 
through this last point, and its intersection with the arc will give 
the radius of an arc concentric with the large circle which must 
be drawn towards the given line. Then, with the required radius, 
again set off arcs from the given line to give a parallel line, as in 
Figs. 99 and 100. The intersection of this parallel line with the 
larger arc will give the centre to use for the connecting curve. 
In every case it will be observed that the perpendicular line from 
the centre of the junction curve to the line, or the line joining the 
centres of the two curves, will give the exact termination of the 
junction curve. 

Fig. 102 is practically the same as Fig. 101, with different radii 
Fig. 103 shows two circles of different size joined by two 



BEAWING GIBGULAB LINES, 63 

curves of equal radii, set off upon the same principle as Figs. 101 
and 102. 

Fig. 104 shows a straight line cutting a circle and joined by 
small curves on the inside. After drawing the circle and straight 
line, take the required radius of connecting curve and draw a 
short arc on the inside of large curve — say, on the centre line — 
and from the main centre draw an arc concentric with the large 
circle, but inside it. Then, with the required radius, obtain a line 
parallel to the given line, and the intersections of this parallel 
line with the large arc will give the centres for the connecting 
curves. 

Fig. 105 shows two given parallel straight lines which are to be 




Fig. 104. — Curved Joins. Fig. 105. — Ogee Curve. 

joined by an ogee or reversed curve. Select a point on one of 
the lines from which the curves may start, draw a horizontal line 
and also an inclined line, making an angle of 60^ with it. The 
latter line produced to cut the other given straight line will mark 
the termination of the curves. Bisect this inclined line, and it 
will give the junction point between the two curves. Bisect each 
half of the inclined line and produce the bisection to meet the 
horizontal lines, to give the centres for the curves. Before draw- 
ing the curves, join these centres, to see that a straight line will 
pass exactly through the junction of the two curves, and then put 
in the curves with a radius equal to half the length of inclined 
line. This is a very useful curve, and is similar to those used for 
cross-over roads on railways. In architecture the best curves are 
produced from conic sections or freehand Circular curves have a 
harsh appearance. There are, nevertheless, many cases where 
they are necessary or desirable. 

The remaining examples in this chapter (Figs. lOG to 113) are 
all well-known mouldings, whose beauty consists in their 
simplicity. Many beginners will appreciate the ability to make, 
at this early stage, drawings that soon look architectural. There 



64 



PRACTICAL DRAUGHTSMEN'S WORK. 



are many cases where mouldings are intended purely for orca- 
ment, as round the panels of a door ; but there are other cases 
where the mouldings form a definite addition to the strength, as 
at the ends of a cast-iron column. 




Fig. 106. — Ovolo or Quarter-round 
Moulding. 



Fig. 107.— Cavetto or Hollow. 



Speaking broadly, mouldings may be divided into two classes, 
known as Roman and Grecian, the former being compass curves 
and the latter derived from the conic sections. They are used 




Fig. 108. — Cyraa Recta, or Ogee. 



109. — Cytna Re versa- 
Reversed Offeo. 



generally for relieving straight lines by giving variety of shade, 
or for lessening the abruptness of the junctions of various parts. 

In the examples shown at Figs. 106 to 113 a quarter of an inch 
is taken as the unit, the figures marked on the illustration giving 
the number of quarter-inches in each piece. These must not be 



DRAWING GIBCULAB LINES. 



65 



taken as fixed proportions, but merely as suitable sizes for the 
examples. It will be seen that every curve forms exactly a 
quarter of a circle, and very neat junctions should be made where 



(M 



r 



CJ 



(0 



(M 



Fig. 110. — Scape Moulding. 



a 


01 


1 


(N 


1 




u> 


1 
1 


.^s-- 


CM 






(M 





Fig. 111.— -Fillets or Annulets. 




Fig. 11 2. -Quirked Ovolo. 




Fig. 113.— Scotia. 



two curves meet. The dotted lines show that tangent curves 
always meet upon the line joining their centres. 

The heading to this drawing should be in block letters y^in. 
deep, and the descriptions in block letters | in. deep, all upright. 



66 PRACTICAL DRAUGHTSMEN'S WORK. 

It is better to avoid ornamental printing at least until some 
facility has been attained in making plain block letters, as no 
other lettering can exceed this in clearness and neatness. 

There are many other mouldings founded upon these or made 
up by a combination of two or more, and it will be interesting to 
examine a stock of mouldings or a pattern book of machine-made 
mouldings, to see how the sections are made up. Attempts to 
design a moulding should not be encouraged until a good general 
knowledge has been obtained of those in use. It is one thing 
to have a striking outline in section and quite another to see the 
same thing in elevation ; there is much scope for taste in selecting 



Fig. 114. — Semicircular Arch. Fig. 115.— Segmental Arch. 

an appropriate moulding for any purpose, as there is also in 
designing a piece of architectural work. The majority of 
mouldings made up of compass curves are ugly, but there are 
cases where they are appropriate, and that is the excuse for 
making them. 

If buildings containing arches of various shapes be examined 
it will be found that although every arch is made up of a great 
number of lines for mouldings, etc., there is a type underlying 
each different arrangement. Outlines of the commoner forms of 
arches are shown in Figs. 114 to 121. The curves, of course, simply 
show the types, the construction of the arch being on the lines 
shown. In other words, every arch may be reduced to a single 
line, the shape of which indicates the type of arch, and is really 
the foundation of its construction. In connection with the arch 
there will always be the supports— either piers or abutments — 
which receive the weight and thrust. The true termination of 
the arch may sometimes be obscured, as in certain stone arches, 
and at other times perfectly evident, as in brick arches. The 
termination is the skewback, which should be always at right 
angles to the direction of the curve ; or, when the curve is struck 
from centres, the skewback is radial from the centre used for the 
adjacent part of the curve. In the diagram given in the follow- 



DRAWING GinCULAE LINES. 67 

ing eight figures the skewbacks and abutments are indicated for 
each arch. 

The first one (Fig. 114) is a semicircular arch of 3 ft. span — 
that is of 1 ft. 6 in. radius — and is a full half circle ; in this the 
skewback is horizontal, and it is popularly supposed that on that 
account there is no thrust, but it is a misapprehension, as there is 
a thrust amounting approximately to one-fourth of the load. 
The semicircular arch occurs very largely in Norman architecture 
(a.d. 1066-1189), and also in Classical architecture. 

The next case (Fig. 115) is a very common form, but properly a 
segment arch, often called a jack arch, or circular arch, or seg- 
mental arch. It is to have a span of 4 ft. and a rise of 1 ft., and 




Fig. 116.— Segmental Arch. Fig. 117.--Tudor Arch. 

the radius must be found by a geometrical construction, thus : 
Mark off the span upon a horizontal line representing the spring- 
ing line, and from that, upon a vertical centre line, mark oif the 
rise ; three points will then be given through which the curve 
must pass. Take these points in pairs, and with any radius a 
little greater than half the distance between them draw inter- 
secting arcs ; through the points of intersection draw straight 
lines which will meet at a point giving the centre from which the 
arch curve is to be struck. 

To set off a segmental arch (Fig. 116) divide the springing line 
into three equal parts, and upon the under side of the middle 
third construct a square, the lower corners of which will give the 
centres to be used. To set off the Tudor arch (Fig. 117) divide 
the springing line into five equal parts ; take three of these parts, 
measured downwards under the central division, for the length 
of a rectangle, one division wide, whose lower corners will give 
the centres for the middle portion of the arch ; the sides of the 
arch have a radius of one division. Draw lines through the 
centres to mark the junctions of the curves, and put in the 



68 



PB ACTIO AL DRAUGHTSMEN'S WORK 



curves so that they do not show a joint. Figs. 116 and 117 are 
sometimes called flat-pointed arches, to distinguish them from 
the earlier lancet and equilateral arches (Figs. 119 and 120). In 
inking-in these examples let the construction lines be very thin 
and neat, and the outlines clear and bold. If any mouldings 
were shown to these arches they would be struck from the same 
centres, so as to give parallel curves. 



/* 




Fig. 118.— Elliptical Arch. 



Fig. 119.— Lancet Arch. 



A true elliptical arch cannot be struck from centres, as it is a 
conic section, but a very fair one may be set out as shown in 
Fig. 118. Divide the springing line into four equal parts, and 
upon the two middle ones construct an equilateral triangle ; then 
the corners of the triangle will give the centres for the different 
curves of which the arch is composed. 





Fig. 120.— Equilateral Arch. 



Fig. 121.— Ogee Arch. 



The lancet arch (Fig. 119), so common in Early English archi- 
tecture (a.d. 1189-1307), has the centres on the springing line, 
and the radius used is equal to one and a-half times the span. 
The equilateral arch (Fig. 120) is the easiest of all to draw, the 
radius being equal to the span. It was much used in the 
Geometrical Period, at the early part of the fourteenth century. 

The next arch is drawn upon the same principles as the ogee 
curve shown in Fig. 121, and with the construction lines given 
requires no further explanation. It is defective as a scientific 



DB AWING CIBOULAE LINES. 69 

arch, but occurs often in the Decorated Period, towards the end 
of the fourteenth century. After that period the arches were 
made flatter, examples of w^hich are the segmental, or tw^o-centred, 
and the Tudor, or four-centred, arches. 

This ink-leg of the compasses works very similarly to the ruling 
pen that has been described in the previous chapter on p. 24, 
so that little further instruction is required. See that the 
nibs are square to the paper, hold the compasses by the joint 




Method of using the Pump. 



between the right thumb and fingers, and use the left hand only 
to steady the point at starting by resting the fingers on the paper. 
Never use two hands to the compasses. The smaller curves are 
not easy to put in with large compasses— a bow pen (Fig. 39, p. 31) 
or small compass (Fig. 36, p. 31) is generally used ; and for a 
number of very small circles, such as rivet-heads, pump bows 
(Fig. 40, p. 32) have a great advantage, and the method of using 
this instrument is shown by Fig. 122. Lines for the small 
printing may now be ruled, and all the lettering put in neatly 
with a steel writing pen. 



70 



CHAPTEE V. 



ELLIPTICAL CURVES. 



In the last chapter circular curves were dealt with, and by a 
very easy transition we pass to elliptical curves, or ellipses, 
commonly called ovals— although strictly an oval is larger one 
end than the other, like a hen's egg (Latin ovum, an egg). The 
ellipse occurs frequently in machine drawing and sometimes also 
in civil engineering and architecture. 




K H B 

Fig. 123. — The Conic Sections, ab Triangle; c d Circle ; ef Ellipse; 
G H Parabola ; J k Hyperbola. 

The principal curves are derived from conic sections, so it will 
be well now to study the different ways in which a cone may be 
cut in the way shown by Fig. 123. A vertical section passing 
through the apex of the cone, as a b, the cut surface will represent 
a plane triangle, and any horizontal section, as c D, will form a 
circle. 



ELLIPTIOAL CURVES. 



71 



A section in any direction not horizontal, so long as it passes 
only through the sloping sides of the cone, as e f, will form an 
ellipse ; if the section be nearly horizontal, the ellipse will be 
nearly a circle, and if it be nearly parallel with the slope, it will 
be long and narrow. 

A section cutting anywhere through the t^se and parallel to 
the sloping surface, as G H, will form a parabola : while a vertical 
section, as J k, not passing through the apex will form a hyper- 
bola. These two may be called open curves, because they do not 
form a closed figure, unless the straight base be taken as part of 
the figure. It will help to impress the derivation of the different 
curves on the mind if the cone be drawn and the lines of the 
section marked on it. The cone may also be shaded by lines as 
<5hown, observing that on the left the shading is narrow and 





^ig. 124. 



Fig. 125. 



I 
<? 

(f) 
Fig. 126. 



darkest at the outer edge, while on the right it is much broader, 
but darkest a little way off the edge and lighter towards each 
side, giving the effect of reflected light on the right-hand side. 

Whenever a circle is viewed otherwise than at right angles to 
its plane it appears as an ellipse, though of course its real shape 
remains unaltered. Wheels, pulleys, drums, collars, couplings, and 
many other parts, act the same as the penny referred to in the last 
lesson, .but they form as many ellipses as they have circles in their 
construction. Besides these, there are cases of actual ellipses, as in 
tha elliptical holes cut for handholes in macnine framings, elliptical 
gearing, elliptical arches, elliptical flower-beds, etc, A penny held 
Uf at arm's length towards a window will show different shapes 
according to its position. The full view will be a circle as 
Fi<^. 124, and then by turning it slowly the circle will become 
an ei:ipse, retaining the full depth but getting gradually less in 
width, as Fig. 125, and ultimately showing only a straight line, as 
Fig. 126. Every intermediate position that can be taken between 
Figs. 124 and 126 will give an ellipse, so that there is no fixed 



72 



FBAGTWAL DRAUGHTSMEN'S WORK 



proportion between the two diameters ; thus an ellipse may be 
obtained of any required length and width. 



POINT OF SIGHT 
IN ELEVATION 



PERSPECTIVE BY 
ORTHOGRAPHIC PROJECTION 



PERSPECTIVE VIEW 
PROJECTED FROM THE 
TRANSPARENT PL//<6 



tLEVATlON 
OF RAYS 




POINT OF 
SIGHT IN PLAN 



Yig. 127. — Ellipse Projected from a Circle. 

It has been contended that, although the perspective view of 
a circle is something like an ellipse, it would quickly be detected 
as "out of drawing," but it will be found that the statement is 
correct. The centre lines of the circle will not remain the centre 
lines of the ellipse, and this is where the misunderstanding arises. 
Fig. 127 shows a circle in perspective, with the enclosing square, 
its diagonals, and centre lines. This will be found to be a true 
ellipse. This figure also shows in one view how perspective 



ELLIPTICAL CURVES. 



73 



representations may be derived from ordinary projection such as 
every draughtsman is in the habit of using, and gives an 
opportunity of testing whether a circle in perspective is a true 
ellipse. 

In the lower left-hand corner a square is drawn and a circle 
inscribed ; the diagonals of the square are then drawn, and where 
they cut the circle other lines parallel wdth the sides are draw^n. 
Parallel with two of the sides a line is drawn to represent the 
transparent plane or surface which is to receive the picture, and 
beyond this a point is selected to represent the position of spectator 
or point of sight. The top edge of the square is made coincident 
vfiih the ground line for the elevation, and a height is assumed for 




Fig. 128.— Simple Way to Draw a True Ellipse. 

the spectator's eye directly over the point of sight in the plan. 
Lines or rays are then drawn from certain of the points on the 
boundary of the square to the points of sight, and where the eleva- 
tion rays cut the transparent plane, horizontal lines are projected, 
and the lowest of these intersections is used as a centre round 
which to turn the horizontal intersections in a quadrant to give 
vertical lines cutting the previous horizontal ones. The perspec- 
tive view of the square being thus obtained, a curve is drawn 
through the points so found to represent the circle in perspective, 
&.nd, on testing this, it will be found to be a true ellipse, notwith- 
standing the fact that the back half of the circle appears so much 
smaller (because more distant) than the front half. 

A simple way to draw a true ellipse is shown at Fig, 128. 
First draw the major and minor axes, as a b and c d respectively. 
Then from c or d as centre, with half the length of a B in the com- 
passes, cut A B in the points f and G. These are the two foci. 



74 



FEAGTIGAL DRAUGHTSMEN'S WORK 



Take a piece of string as long as gc+cf, and fasten the ends by 
pins at F and g. With a pencil, as shown, stretch the string, and, 
keeping the pencil in the angle thus formed, swing it round both 
above and below a B to form the curve required. 

Perhaps the easiest way to set oflf an ellipse on a drawing is 
from two circles as shown in Fig. 129. Draw two centre lines 






Fig. 129. — Ellipse Constructed fiom two Circles. 

and describe circles equal to the major and minor axes of the 
required ellipse, say 7 in. and 3j in. ; then draw radii in any 
position, but preferably say every fifteen degrees (15*^). If 
vertical and horizontal lines be now drawn from each radius 
where it is cut by the two circles, these lines will intersect at a 
point in the circumference of the ellipse, and the points may be 
joined by using a French curve as before described. 

An approximate method of drawing an ellipse with compasses 



ELLIPTICAL CURVES. 



75 



to patch up the curve is shown at Fig. 130. Divide the major axis 
AB into three equal parts by the points c and D, and with each of 
these points as centres, radius equal to A c or d b, describe the 
small circles shown, cutting one another in the points e and f. 
Parts of these circles form parts of the ellipse, the remainders of 
the circles being shown dotted. To determine the extent of the 
full lines from each point of intersection, draw lines through the 
centres c and D to cut the circles. Then from centres f and e, 
with radius equal to F G or eh, draw tangent arcs to complete the 
ellipse, as shown. 

The same method can be applied to draw an ellipse of dififerent 




Fig. 130. — Approximate Method of Drawing an Ellipse. 



shape as shown at Fig. 131. With a as centre, and c d as radius, 
mark the point e. Divide the distance eb into three equal parts. 
With o as centre and two of these parts as radius, cut line ab in 
M and N. With m and n as centres and with m n as radius, 
describe arcs intersecting in p and Q. With p and q as centres 
and p D as radius, describe arcs T D v and R c s, and from m and n, 
with radius M A, describe arcs rat and s B v to complete the 
ellipse. Lines drawn from p and q through m and n show where 
the arcs join. 

The method about to be described is not very scientific, but it 
is founded on accurate principles, and is both interesting and 
useful. Suppose we want an ellipse (Fig. 132), 9 in. long by 6 in. 
wide, which would be described by a mathematician as an ellipse 
whose transverse and conjugate diameters are respectively 9 in. 
and 6 in. First draw two centre lines at right angles to each 
other and rather longer than the above dimensions, then measure 



76 



PBAGTIGAL DRAUGHTSMEN'S WOEK. 



off carefully from their intersection in each direction the required 
semi-diameter. Mark the horizontal line a, the vertical line b, 
the half minor axis a b, and the half major axis b c. Now 




Fig. 131. — Another Approximate Method of Drawing an Ellipse. 

prepare a slip of writing or drawing paper (Fig. 133) with one 
edge quite smooth and even ; make a mark on this edge near 
one end, and sketch a hand pointing against the mark. Then 




Fig. 132. — Drawing Ellipse with Paper Trammel. 

measure off a distance equal to the semi-diameter a b and make 
another mark, putting a against it ; next measure off from the 
same point a distance equal to the semi-diameter b c, pu^^^ting b 
against it. This paper trammel is now complete, and nady for 
service in constructing the ellipse ; it is shown in course of use 
on the drawing (Fig. 132) by dotted lines. 



ELLIPTICAL GUBVES. 



77 



If point A of the trammel be kept on the A line of the figure, 
and B on the B line, the hand will show where a pencil dot is to 
be made to give a point in the curve of the ellipse. Of course, 
it will be wise to go steadily round and put the dots about i in. 
apart, seeing that they look even before joining them up. When 



W - - 


• - - -de- - 
<- - ad - • 




IB 

PAPER 


A 

TRAMMEL. 


i 








— " 



Fig. 133. —Paper Trammel for Drawing Ellipses. 

this is done, a light thin line should be sketched continuously 
through all the dots, endeavouring at the same time to correct 
any irregularities. When the pencil curve looks all right, it may 
be inked in with the assistance of a French curve, such as is 
illustrated on p. 36. This thin slip of wood must be used with 
caution, finding a part that will fit the curve, say, from d to e 




Fig. 134.— Use of French Curve. 

(Fig. 134), and drawing only from / to g, so that there is always 
a piece at each end that appears to fit but is not used. By this 
method an ellipse will be obtained as regular in its outline as a 
circle drawn with compasses. It is worth taking some pains 
over it, because a good drawing of a machine may be spoilt by 
some little piece of curve, elliptical or otherwise, looking thick 
and ragged compared with others put in by compasses. 

The method used by joiners and patternmakers to strike an 
ellipse is shown in Fig. 135. In place of the paper trammel used 
in Fig. 132 a piece of lath is taken, with a pencil inserted at Q::^*, 



78 



PR AG TIG AL DBAUGHTSMEN'S WOER. 



and French nails or stout pins at A and B. Then two straight- 
edges are placed against the major and minor axes so that the 
trammel may move along by the sliding of the pins over the lines, 
and each quarter of the ellipse can be struck in a continuous 
curve. The focus of an ellipse bears somewhat the same rela- 
tionship to the curve as the centre of a circle does to the circle, 
but in the ellipse there are two of these centres or foci. 

These are the points where the gardener puts pegs in the 
ground when he throws a loop of string over them to make a 




Fig. 135. — Patternmakers' Method of Drawing Ellipses. 



so-called oval bed, although he will have to make several trials 
before he can hit upon a suitable proportion, through not knowing 
the proper method of setting about the work, which is done in the 
way shown by Fig. 136. First set out the two centre lines and 
decide what the two diameters shall be ; then take the distance 
A B for radius, and wdth a string and couple of pegs for compasses, 
from the centres c and d strike arcs intersecting on the line A b in 
the points Fj Fg ; then Fi and F2 are the foci of the required ellipse. 
Drive pegs in at these points, and take a piece of string long enough 
to go right round Fj CF2, tie the ends to make it continuous, slip it 
over the pegs Fi and Fo, and then with a stick p, starting at c, the 
whole ellipse can be struck in one continuous curve. There is no 
need to go into the garden in order to practise this method ; two 
pins and a piece of cotton on a sheet of writing paper will 
demonstrate the problem equally well. 



ELLIPTICAL CURVES. 79 

Brick arches are generally formed to the segment of a circle, 
and frequently occupy the exact half circle, when they are called 




Fig. 136.— Gardener's Method of Constructing an Ellipse. 

semicircular arches. In the ordinary way, an arch crosses at 
right angles to the opening it spans, but in the case of a railway 




Fig. 137.— Plan of Skev/ Arch. 

crossing a road diagonally, or a road crossing a canal similarly, a 
skew bridge is necessitated. In the accompanying plan (Fig. 137), 
a bridge is shown crossing a roadway with an angle of skew at 



80 



PRACTICAL DRAUGHTSMEN'S WORK. 



ab d o{ ZO degrees. The plan does not show whether it is a 
girder bridge or an arched bridge, but it would very likely be a 



l^v V 



O 

<- -- 



UJ 

- -o 



' -f-^ 

y- - 

J 
hi 









'-"^^ 



"■^'.xO 



■ <h 



A 






X\ 



'/-- 



■6z M^*^' 



,iO 



.-aO> 






Fig. 138.— Elevation of Skew Arch. 

brick arcli having a semicircular soffit, that is, the section straight 
across the road in the direction a b c will show a semicircular 
outline on the underside. 

In whatever way the a^rch may be built, whetlier with spiral 



ELLIPTICAL CURVES, 81 

courses, as in a proper oblique arch, or in plain rings stopped off 
as they reach the face, as in some modern arches, the actual 
elevation on the face of the arch will be a semi-ellipse. We are, 
however, not tied to the semicircle for the normal section ; we 
may have a segment of a circle, or a semi-ellipse, or any other 
outline which may be preferred, as the method of working given 
in the diagram answers equally for all shapes. As the reader 
has learnt to draw an ellipse, it will give the most practice to 
assume the normal section to be a semi-ellipse, and then the true 
elevation on face of arch will be another semi -ellipse with a 
longer major axis. To obtain this elevation (Fig. 138), draw a 
horizontal line, and at one end set off the angle of skew 30 
degrees, and cut off the new line to a length of 30 ft., according 
to the scale it is intended to adopt, say J in. to 1 ft. Then 
bisect that line, and set off at right angles to it from the centre a 
distance of 10 ft. to represent the rise of the arch, and by one 
of the preceding methods construct a semi-ellipse to show the 
section across roadway. 

It often happens that very flat curves, or those with large 
radius, have to be drawn, and these the compasses will not reach. 
Some compasses, as described on p. 23, have a lengthening bar 
that will enable curves of 12 in. to 15 in. to be drawn, but this 
may not be sufficient. Then a trammel may be used, consisting 
of a lath with a sliding point and sliding pencil, enabling curves 
up to, say, 10 ft. radius to be drawn. There are, however, many 
cases where it is not convenient to use a trammel or any such 
instrument owing to the absence of a place to rest upon for the 
centre, and some more compact and ready means must be found. 

In Fig. 139 let A B be the span and c d the rise of the required 
circular arc. With centre A and radius A B describe arc B e H, 
and from centre B with radius B A describe arc a f G. Through 
D draw^ ADE andBDF. Along the curves AG and bh at each 
side of E and f set off any convenient number of equal parts 
Join the points thus marked on the arcs with the centres from 
which the" arcs were struck, then the intersections of the lines 
from E H with those from F a will give the required points for the 
curve from a to d, and the intersection of the lines from e b 
with those from F G will give the points for the part of the 
curve D B. 

This results in a nearly true circular curve, but there are 
many cases where the curve need not be truly circular, and, as 
F 



82 



PRACTICAL DRAUGHTSMEN'S WORK 



a fact, when the rise is not more than one-sixth of the span it is 
almost impossible to distinguish between a circular arc and a 
parabola. This being so, we may adopt an easier method 
(Fig. 140), which gives clearer intersections. Let kl be the 




span and M N the rise of the required curve ; set k o perpendicular 
to K L and equal to twice M N, so that the point o lies in l n 
produced. Divide ok into any number of equal parts, and 
draw lines toward point L ; divide K M into the same number, 
and draw vertical lines ; the intersections will give points in the 
curve from k to N. For the curve from n to l repeat the operation 



ELLIPTICAL CUBVES. 



83 



on that side— viz. by drawing the perpendicular at L, dividing it, 
and drawing lines towards K, then vertical lines on M L to give 
the intersections. 

What is called a straight arch is very much used in brickwork 
over window openings. It is sometimes called a camber arch, 
because of the camber or slight curve given to the soffit. This 
camber is about f in. to a span of 3 ft., or, say, J in. per foot, and 
must be worked to by the bricklayer, but is not usually show^n 
upon the drawings. Girders and girder bridges are made with a 
camber on the underside to improve the appearance ; these alst) 
are not indicated on the drawing except by a written note, the 



-1^ 



r - 



1 "^""---^^ 
l"" "" -J ^ ' "" 

• '^^ I- 




_!,__'__" ! !__L_ 



K M 

Fig. 140.— Parabolic Method of Setting Out a Flat Arc. 



reason being that to draw them actually as constructed would 
involve considerable trouble with no corresponding advantage. 

The parabola is such a very useful curve that no apology is 
needed in presenting some other methods of construction. It is 
the curve of equilibrium for an arch uniformly loaded across the 
span ; it is also the curve of longitudinal stress in a girder headed 
uniformly throughout its length. Besides these it enters in other 
ways into the shape of beams designed for uniform strength. 
The nature of the curve may be explained by supposing it to be the 
locus (that is, the successive positions or the route) of a travelling 
point, such that for any distances travelled in one direction it is 
displaced at right angles to that direction by an amount propor- 
tional to the square of the displacement first mentioned. 

Useful methods of drawing a parabola are shown on the dia- 
gram (figs. 14X or 142) for one half the curve, the other half being 



84 



FRAG TIG AL DRAUGHTSMEN'S WORK. 



similar. Draw horizontal and vertical lines representing the 
base and axis, mark off the semi-diameter and the height, and 
complete the rectangle. Divide the semi-diameter into twenty- 
equal parts by vertical lines, and number them as shown. Now 
place a straight-edge or the side of a set-square in line with the 
lower left-hand corner of the figure and the point marked 10, 
and draw a line across the first division ; from the termination of 
this line draw towards point 11 across two divisions, and from 
the new termination draw towards point 12 across two more 



VERT, EX 




SEMI BASE OF PARABOLA 

Fig. 141.— Parabola Constructed by Continuous Tangents. 

divisions ; and so on until point 19 is reached, when it will be 
found there is only one division to draw the last line across to 
point 20. By this means a parabola wdll have been formed 
approximately correct, but actually formed of short, straight lines. 
The tangent lines in the figure are shown drawn through to the 
top line, but in practice this is not necessary, and the verticals 
need not all be drawn through so long as they contain the curve 
and reach the top line between points 10 and 20. 

The annexed diagram (Fig. 142) shows three methods of 
setting off a parabola, in one of which the law first stated is 
clearly shown ; by the other methods it is not so evident. Draw 



ELLIPTICAL CURVES. 



85 



horizontal and vertical lines for the base and central height of the 
parabola and mark off a diameter of 12 in. and a height of 6 in. 
Complete the parallelogram, divide the base into sixteen equal 
parts, and draw vertical lines. Then for method 1 divide the 
vertical line at the extremity of the base into eight equal parts, 
the same number as in the semi-base, and from the vertex of the 
parabola draw lines radiating to these division points ; the 
intersections with the vertical lines will give points in the curve 
which should then be sketched in neatly by hand and lined in with 
a French curve. If the lines are numbered as shown there will 
be no difficulty in marking the correct points for the curve. 




Fig. 142. — Throe Methods of Constructing Parabola. 



Method 2 is based upon the nature of the curve explained 
above, displacement at a distance of 1 being 1 squared 1^ = 
1 X 1 = 1 ; at a distance of 2 = 2^ = 2X2 = 4; at a distance 
of 3 = 3^ = 3 X 3 = 9, and so on, so that if we had a total 
height of sixty-four parts we should measure downwards from 
the top line, on each of the verticals, distances of 1 part, 4 parts, 
9, parts, etc. As the total height is 6 in., we take g^ of 6 in., ^ of 
6 in., -^^ of 6 in., and so on, i.e, g^, Jf, f I of an inch, etc., and 
then draw the curve through. Method 3 is the complement of 
the last, and they are both very interesting because of the peculiar 
repetition of figures making it easy to remember the order. The 
total height is sixty-four parts, because we have eight divisions 
in the semi-parabola, and 8 X 8 = 64. If we had taken twelve 
divisions we should have had 144 parts in the height ; the second 



86 FRAGTIGAL DRAUGHTSMEN'S WORK. 

method would have commenced with 0, 1, 4, 9, etc., 144ths, and 
have continued beyond 8 X 8 up to 12 X 12 144ths. So in the 
third method with twelve divisions we should commence with 
12 X 12 and have continued 13 X 11, 14 X 10, 15 x 9, etc., to 
23 X 1, and 24 X 0. 

Water spouting from an orifice, a shot fired from a gun, 
or a stone thrown from the hand, all describe parabolic curves 
in falling to the ground, and the line of flight is called 
the trajectory. In this connection it may be interesting to 
note that a ball fired from a level gun over a horizontal 
piece of ground would describe a parabola, and w^ould reach 
the ground in the same time as a ball simply dropped 
from the mouth of a gun, the reason being that the fall 
of both is caused by the force of gravity acting equally on 
them. 

The hyperbola is another of the conic curves. It is the curve 
formed on each of the faces in chamfering the bright hexagonal 
nuts used in machine construction. Sometimes a neat draughts- 
man will discover that the compass curve commonly used for 
showing the chamfering in the elevation of a nut cannot be made 
to fit the 45° line at the corner, but he may not know that 
this is because the curve is a hyperbola and that only an approxi- 
mation can be drawn by the compasses. When steam expands 
in the cylinder of a steam engine the pressure is reduced, and if 
a horizontal line be drawn to represent the stroke of the piston, 
and the vertical heights representing the pressure as it changes 
be set off upon it, the points will approximate to a hyperbola, 
hence the expression "hyperbolic expansion curve." 

On comparing this figure with the parabola it will be seen 
that the legs, as they may be called, of the hyperbola are straighter, 
and that the curved part of the former is narrower in proportion 
to the size. 

There are several methods of setting off this curve, and the 
first (Fig. 143) illustrates one of its properties. Draw a hori- 
zontal line, called the asymptote, and set off any number of equal 
parts 1, 2, 3, etc., say 1^ in. each ; at set up a perpendicular 
8 in. long, or sixteen half-inches, giving point marked 16. This is 
to be the starting point of the curve. On point 1 set up half the 
height, or eight half inches, on point 2 set up four half-inches, on 
point 3 set up two half-inches, and so on for as many divisions as 
have been made, each height being half the preceding. Now it 



ELLIPTICAL CURVES. 



87 



will be seen from this case that the hyperbola is a curve which 
continually approaches a straight line but never meets it, because, 
however many divisions may be taken, the distance from the 
asymptote is always half the last distance. 

In the next figure (Fig. 144), two asymptotes are drawn at 
right angles, and ^-in. squares marked off to facilitate the drawing 
of the curve. The axis of this hyperbola will be the diagonal of 
the figure, the curve being symmetrical on each side of it, so that 
this line passes through the vertex or highest part of the curve, 




1 








• 










4 






\ 




y 

y 








\ 














^ 


-^ 


^ 




TS 



■^g. 144.— Hyperbola. 



3 4 5 e 

Fig. 143.— Hyperbola. 



and the two sides or legs may be produced infinitely, but after 
about one more division each way the curve becomes practically 
a straight line. 

To set out a hyperbola to fill a given rectangle (Fig. 145), 
draw a horizontal line A B, 6 in. long, representing the base of a 
hyperbola, and a vertical line c D bisecting it, 4 in. long, for the 
height to the vertex d. Produce cd, making de equal to CD. 
Divide the base a b into any even number of equal parts, and 
the vertical lines above A and B each into half the number of 
parts ; draw the converging lines as shown, and a curve drawn 
through the intersections thus formed will be a hyperbola. 

The foundation for screw threads and for spiral staircases is 



88 



PRACTICAL DRAUGHTSMEN'S WORK. 



the helix. If a piece of paper be cut to the shape of a long right- 
angled triangle and rolled round a cylinder as in Fig. 146, the top 
edge of the paper will form the helix, and the pitch is the height 
reached in going once round. This helix is sometimes described 
as an inclined plane wrapped round a cylinder, which is practic- 
ally what this experiment shows. Now, as in travelling up an 
inclined plane one continues rising at a regular rate, so* on a 
spiral staircase every step is actually the same height and width ; 
but in a picture of such a staircase the steps look narrower at 
the sides of the picture and wider in the middle, because the 





Fig. 145.— Hyperbola. 



Fig. 146.— Helix. 



outer edges are not in one plane ; being bent round to a 
cylindrical form, the sides are foreshortened. 

This will be better understood after the curve is drawn as shown 
by Fig. 147. Commence with the centre line ab. From point c 
in it describe a semicircle D A E of 3-in. radius, and through c draw 
the base line d c e, which should be horizontal. From d and e 
draw the vertical lines D F, E G, each 9 in. long, and then draw 
the upper horizontal line F B G. The rectangle D F g E represents 
the elevation of a cylinder. The semicircle D a E represents the 
plan of the front half of the cylinder, and upon it are set out the 
successive steps. With radius c d, mark off d l, am, an, and 
E o, then bisect d m, M L, L A, A o, on, and n e ; this will hav3 
given twelve equal divisions upon the semicircle from which 
vertical lines must be drawn as shown. If the curve is to ris2 



ELL IF TIC AL CURVES. 



89 



from point d with a pitch of 4 in., it will rise half that, or 2 in. in 
the front or visible half and 2 in. in the back or hidden half, and 
so on for any number of turns of the spiral ; therefore draw 
horizontal lines, half pitch apart, through h, t, j, and K, as the 
same curve will be found to repeat itself in each of these 
divisions. 

As twelve divisions have been made on the semicircle, so 
twelve divisions must be made between d and H, and horizontal 
lines drawn through as shown. This will give a series of inter- 
sections through which the curve must be drawn ; one along and 
one up, two along and two up, and so on for the right points. 
When this much of the curve has been put in, the remainder 



■^ D H 


J K F 


M,,^'-'- '^1 


xr:"^"';;;'!"^^"' '/ 


:»^- a ^,, 


\-- 




H^. ,-•'*"' ■ 


: Y' :•! H"^"; / 


\ r f^ 


\ 




l/ 


Wm h 


\ 4-—/- 


-V 




iVf./ 






-jijitili;;;' / 


\ ' ' 


\ 




a; c 

%i-V""' 

/^id. ._ J 


J 1 1 '_' i-lA-ixlu- -<-_ _ _ _ 


\ I * 

V-r—i 




B 


*> — ■ 




\ • ' 








Fig. 147. — Projection of a Helix. 



can be most readily drawn by using the half pitch lines i, J, 
and K, and with the compasses or bow pencil marking off upon 
the verticals all the places where the curve is one division up or 
down, then two divisions, and so on. Dot the curve on the back 
of the cylinder, and observe that, if correctly drawn, the helix 
will not form a point at i or k, or similar parts, but will really be 
vertical for a very small distance, giving the effect of a rounded 
turn. 

The curve, with which this chapter will close, is called an 
" entasis, '^ and was designed to meet the aesthetic taste of the 
ancient architects. They knew that a long column was 
scientifically inaccurate if made parallel, owing to the greater 
weight carried by the lower part, and they thought the straight 
taper looked ugly, so they made their columns with a slight 



90 



PBAGTIGAL DRAUGHTSMEN'S WORK, 



swell in the diameter between the two ends. The optical effect 
of the entasis is to increase somewhat the height. Metal under 
compression bulges before it gives way, and hence the bulging 
here gives the feeling of supporting a load and not of being 




Fig. 148.— Entasis of Column. 



merely ornamental ; besides that, a column with a straight taper 
appears to be slightly hollow at the sides. 

In the illustration (Fig. 148), the diameters are taken very 
large in proportion to the length, in order to show the method 
and result more clearly. There are various ways of setting off 
this curve ; the one shown is known as Tredgold's. Suppose 
the length between the mouldings of the cap and base to be 



ELLIPTICAL CURVES. 91 

12 Id., the top diameter 3 in., and tlie bottom diameter 4J in. ; 
these dimensions might represent a heavy cast-iron hollow 
column to a scale of 1 in. to 1 ft., but the result is altogether 
too stumpy for a stone column ; nevertheless, the same principles 
apply whatever the length may be. Draw the centre line A B c, 
making b c equal to the length ; then draw the two diameters 
D E and F a. Upon d e construct a semicircle D a e, and from f 
and G, drop perpendiculars to meet the semicircle in points H i; 
then divide the arcs D H and i e into any convenient number of 
equal parts, and the height BC into the same number of parts. 
Draw horizontal lines through the divisions on the centre line, 
and vertical lines to meet them from the divisions on the semi- 
circle ; the intersections will give points in the entasis, and a 
French curve may be used to obtain a properly Hewing curve 
through the points. 

The curves described in this chapter have been specially 
adapted for working on sheets of drawing paper, and when com- 
pleted the set of twelve sheets will certainly be interesting, and, 
it is hoped, will also be useful to the draughtsman. 



92 



CHAPTER VI. 

PROJECTIOX. 

It will be advisable to give some attention to projection before 
going on to shading and shadows. The method of putting a 
plan below an elevation, and a section at the side of it as usually 
practised by draughtsmen, is known technically as orthographic 
projection on vertical, horizontal, and profile planes. The general 
idea of merely drawing the various parts exactly in the same line 
in the different views, or opposite each other, is very simple, but 



Fig-. 149. 



Projections of Lines. 



f 
I 

I 


Fig. 150. 



cases arise where a draughtsman who has not studied descriptive 
geometry finds himself unable to proceed, as, for instance, when 
parts are not at right angles to one or other of the planes. The 
ease of executing ordinary cases of projection, and the difficulty 
of overcoming the unusual cases, are well illustrated in the 
accompanying diagrams (Figs. 149 to 155), in which the following 
seven problems are worked out, but only the last two will require 
a detailed explanation, x y is the line of intersection between the 
vertical and horizontal planes, which are here supposed to be 
laid flat on the paper, one above and one below the line. 



PROJECTION, 



93 



Fig. 149. A line Ij in. long, touching the vertical plane, and 
at right angles to it, parallel with the horizontal plane and 1^ in. 
above it. 

Fig. 150. A line li in. long, touching the horizontal plane 
and at right angles to it, parallel with the vertical plane, and If in. 
rem it. 

Fig. 151. A line ij in. long, parallel with both planes, and 
1 in. from them. 

Fig. 152. A line Ij in. long, parallel with the vertical plane 
and 1 in. from it, | in. above the horizontal plane, and making 
an angle of 45^ with it. 




/ 



^ 



Fig. 151. Fig. 152. 

Projections of Lines. 



Fig. 153. 



Fig. 153. A line li in. long, parallel with the horizontal plane 
and 1 in. above it, touching the vertical plane, and making an 
angle of 30° with it. 

Fig. 154. A line 6 in. long, touching the intersection of both 
planes, making an angle of 30° with the horizontal plane and 25« 
with the vertical plane. 

Fig. 155. An oblique plane cuts the horizontal and vertical 
planes, making an angle of 60° with the former and 45° with the 
latter ; show the traces of its intersection. 

In Fig. 149 the length of line is measured from x Y in the 
plan, and the height from x Y in the elevation. In Fig. 150 the 
reverse. In Fig. 151 the length is measured in either plane, and 
the distance in both. In Fig. 152 the length of line is measured 
in the vertical plane, where its full length can alone be seen. In 
Fig. 153 the length is measured in the horizontal plane for the 
same reason. In Fig. 154 the line is inclined to both planes, and 
annot be measured off directly, as in the previous cases. First 
measure the required length of line a ^ on x Y, then from point a, 



94 



phagtigal dbaughtsmen'S' work. 



with radius a 6; describe the arc cbd, making cab 30^, and 
bad 25^. Then a c represents the line at an angle of degrees 
from the vertical plane, and ad the line at degrees from the 
horizontal plane. In each case the line has to swing round on a 
vertical axis through a to reach its required position ; all we 
know at present is that one end of the line will be at a and the 
other somewhere in the lines c e and df, parallel with x Y. Drop 




Fig. 154. — Projection of Line. 

perpendiculars from c and c?, cutting XY in ^ and A, then ag 
will represent the line in plan when raised up to the required 
angle from the horizontal plane, but coinciding with the vertical 
plane. Now by radius ag swing it round to cut/cZ in point i\ 
then a i will be the true plan of the line. In the same way ah 
represents the elevation of the line when lying on the horizontal 
plane, but making the required angle with the vertical. Now 
from the centre a with a radius a h describe the arc h k, cutting 



PBOJEGTION. 



95 



cein point k, then a k will represent the true elevation of the 
line under the required conditions. If correctly drawn, point k 
ought to be vertically over point ^. 

Fig. 155 presents a rather more difficult case. The principle 




Fig. 155. — Piojection ol: Line. 

upon which it is to be constructed is to assume a sphere whose 
axis is X y, to the surface of wliich the required plane shall be 
tangent. Draw a line at right angles to x Y, cutting it in any 
point a. From point a as a centre with any radius describe the 
circle bed to represent the sphere just mentioned. Draw lines ef 



96 



PBAGTIGAL DBAUGHTSMEN'S WORK. 



and gh tangent to the circle at c and b, and making the required 
angles fea 60^ and agh 46^, From a, with radius ag, 
describe the arc g i, and from a, with radius a e, describe the 
arc €j\ then from points / and A, tangent to these last two curves, 
draw the required traces /A;, A Z:, meeting accurately in point k 
when properly drawn. The rationale of the process is that^^c 
and ejb are parts of a conical surface to which the plane is 
tangent. It must be noted that the sum of the two given 
angles must always be between 90^ and 180^ ; at these extremi- 
ties the traces of the plane will be parallel with x Y when the 
combined angle is 90°, and perpendicular to it when the combined 
angb is ISO''. 

For working drawings of buildings or machines the ordinary 




Fig. 156.— Brick in 
Angular Projection. 



Fig. 157.— Shaded Sketch of 
a Brick in. Angular Projection. 



plan, elevation, and section are best suited, and are clearly 
understood by most, if not all, persons requiring to use them. 
To persons unacquainted with draughtsmen's work they convey 
only a vague idea of what they are intended to represent, and 
this is why perspective drawings are so much in vogue for 
representing the complete view. Perspectives are simply repre- 
sentations of objects as they would appear in a good photograph. 
Formerly any printed illustration had first to be drawn out by 
hand, so that its accuracy was largely dependent on the skill of 
the draughtsman ; the difficulty was most pronounced in the 
case of machines, as any old journal or catalogue will testify. ISTow 
photographs can be adapted for reproduction, and illustrations of 
machines are produced with exactness and at very small cost. 

A still simpler method of projection may be applied to small 
details, which is often incorrectly called isometrical projection ; 



FUOJEGTION, 



97 



strictly, it is pseudo-isometrical (that is, false isometrical), but is 
conveniently known as " angular projection.'^ It is based on 
exceedingly simple rules, which may be summarised as follows : 
Horizontal measurements are taken along lines inclined at ZO^ 
to the base line, and vertical measurements on vertical lines- 
This will be made clear by taking the drawing of a brick (Fig. 156) 
say, 9 in. by 4j in. by 3 in. (that is, large enough to include thick- 
ness of joints) to a scale of half full size. 

Let one corner of the brick (Fig. 156, p. 96) touch the base line, 
then draw a vertical line cut oif 3 in. long, and lines inclined to the 
base 30° each way cut off 44 in. and 9 in. long. Draw vertical 
lines from the ends of the inclined ones, and inclined lines from 







Fig. 158. — Iron Grating in Angular Projection. 

the end of the vertical ; then two sides of the brick will be 
completed. Next, draw inclined lines from the farther corners of 
the two sides to meet above and the brick will be completed in 
outline. To obtain the frog or key on top of the brick, supposing 
the flat margin to be f in., measure | in. from each angle and 
draw intersecting lines. To obtain the curves at the angles of the 
frog in hand-made bricks, suppose them to be in reality i-in. 
radius, the compasses may be used at radii of i in. and | in , as 
shown ; this is necessary to give the effect produced by viewing 
the curves on an inclined surface. 

An angular projection has the advantage of appealing more 
directly to the uneducated eye than the ordinary plan and eleva- 



98 PEAGTIGAL DRAUGHTSMEN'S WORK 

tion do. It should never be back-lined as ordinary plans are, for 
tlie reason that relief is already effected, and back lines would 
only reduce the effect. Angular projections may, however, be 
colon re i, and shaded if desired, as in Fig. 157. In further illus- 
tration of the subject, a small cast-iron gratinp; is shown (Fig. 158), 
i in. thick, bars and margin 1 in. wdde, openings Sin. by 2 in. 

The angular projection, shown above, has the advantage over 
either perspective or true isometrical projection, that an ordinary 
2-ft. rule may be used upon the drawing to ascertain any of the 
dimensions. For showing the details of joints in carpentry and 
joinery, angular projection is especially appropriate, and it will 
soon be found by the draughtsman that the angular directions of 
30 degrees each way for the horizontal lines need not be adhered 
to when some other angle will be more convenient. Convenient 
and simple as this is for details, it would not be suitable to take 
the place of perspective for complete views of houses, as the eye 
w^ould then revolt from what would appear to be distortion. The 
eye is so accustomed to true perspective in nature and the fairly 
accurate representations of photographs and artistic sketches, that a 
house in angular projection would appear to be swelled out 
behind, because where one expects to find the taper, no taper 
w^ould be given. If the simplest possible outline of a house 
be drawn in angular projection, it will serve to show the method 
by which any required points are found, so that any other case 
that may arise may be worked out on the same principles. 

Draw first a plain front and side elevation (Figs. 159 and 160), 
so as to get the various parts in their right proportions, then, 
remembering that vertical lines remain vertical, while horizontal 
lines are drawn at 30° from the horizontal in either direction, no 
difficulty will be found in completing the lower portion of the 
house, the measurements being taken in the same direction as 
the various lines are drawn. For the roof it will be seen that if 
the position of the ridge can be found, the hips will simply be 
drawn up from the angles to meet it. Bisect the eaves line on 
the visible end of the house and draw a line through at 30^ from 
the horizontal to meet the other side ; bisect this line and set 
off half the length of ridge on each side of the bi-section, and from 
the extremities of the ridge length draw vertical lines, cutting 
them off at a height equal to the height of ridge above eaves, as 
seen in elevation, and join the ends. This will give the ridge itself, 
and, the ends being joined to the four corners, the hips are produced. 



FROJEGTION, 



99 



To put on the chimney stack, observe first that the penetration 
of the roof in the front elevation is obtained by noting the 
distance vertically down from the ridge to where the sides cut the 
roof planes in the end elevation. Then draw a vertical line from 





t 
1 






t 


'0 






1 


\ 




J II 


^T-- 


15 o- 


~^ 





_:*_ 


- — 5 


— 7 — r 

>0 0- 








--> 


^30^ 












t 




P 

CO 











Fig. 159.- Side Elevation. 



Fig 160.— Front Elevation. 




\± 



Fig. 161. — Angular Projection. 

the centre of the ridge in the angular projection, cut it off to the 
height of the chimney stack, and the top point will be the centre 
of upper end of stack. Through this point draw centre lines at 
30° each way and mark off the width and breadth of the stack, 
and through the four points thus found draw four lines parallel 



L.ofC. 



100 



FBAGTICAL DRAUGHTSMEN'S WORK, 



with the two centre lines. Now draw vertical lines downward 
from the three near corners and cut them off equal in length to 
the height of the stack on the end elevation. Drop a vertical 





Fio-. 162.- Sketch of Cuhe. 



Fio 



163. — Geometrical Constr action 
of a Cube. 



line from the centre line at top of stack down the wide face to 
meet the ridge, and join up the intersection lines as shown in 
Fisj. 161. 




Fig. 164. — Method of Constructing Isometric Scale. 

Before concluding this chapter on angular projection, it will 
be interesting to see the principles and application of true iso- 
metrical projection. It is based upon orthographic projection — 
that is, the rays of light proceeding from the outlines of the 
object travel in parallel lines, and not in converging lines as in 
perspective. In this it very much resembles the angular pro- 
jection just illustrated, but it differs from that in having the 



PROJECTION. 



101 



inclined lines all foreshortened to make a true projection. For 
instance, if a cube of 3-in. side be drawn in isometrical projec- 
tion, the edges will be foreshortened to about 2| in. to make a 



v^oo-^ 




INS. 12 3 6 3 O 

NATURAL SCALE 
Fig. 165. — Isometric Scale. 

true representation ; or, more accurately, the natural scale is to 
the isometrical as 1 to y f or, roughly, as 11 to 9. In this 
method the object is supposed to be tilted up to show three 
faces ; or, taking a cube as best illustrating the principles, it is 




Fig. 1G6. — Example of Isometric Projection. 



placed so that a direct line from the eye passes diagonalTy 
through the cube as shown in shaded sketch (Fig. 162), or 
geometrically by the outline (Fig. 163). Certain terms are 
used in describing the different parts of the figure ; they are 
—A A, isometric axes ; b, the regulating point ; c c c, isometric 
lines ; D D, isometric planes. The scale may be constructed 
readily by the use of T and set squares as shown, the sketch 



102 



PEAGTIGAL DRAUGHTSMEN'S WORK. 



(Fig. 164) giving the method, and Fig. 165 the result. As an 
example of the application, the end of a one-brick wall is 
shown (Fig. 166), from which it will be seen that there is no 
advantage over common angular projection, for which an ordinary 
scale can be used. 




Fig. 167.— Method of Projection 
at an An"le of 45°. 



In drawing an elevation, ditficulty sometimes is experienced 
when one face of the work, or one side of the building, is not 
square to the front or parallel with it. Common instances are 
shown on the accompanying diagram (Fig. 167), and the method 
of projection scarcely requires any explanation. Draw first the 
natural elevation and plan of the window opening to the required 
scale (Fig. 107). Then assuming that the wall makes an angle of 



FROJEGTION. 



103 



45 degrees with the spectator, draw the plan of it, marking the 
centre line, and also a cross centre line for face of arch. Project 
lines upward from each angle, and also from the centre line at 
face of and back of arch. Then from the elevation project lines 
from each point to intersect those drawn from the angled plan, 
and draw in the straight outlines. 

The circular curves in the elevation will become elliptical in 




Fig. 168. — Projection at an Angle of 45®. 

the angled elevation, but they can be obtained by intersections, 
the same as any other parts of the outline. A point on any part 
of any curve in the elevation as a, being projected down to the 
plan as 6, transferred to the angled plan as c, and projected 
upwards to intersect at d^ with the horizontal projection from the 
' same point, shows the method by which the whole outline may 
be obtained ; a sufficient number of points being found, the 
curve is sketched through by hand and afterwards inked in 
with the aid of a French curve, such as is described on p. 36. 

The illustration (Fig. 168), showing part of a gantry, is upon 
the same principles, and there can hardly be found any difficulty 
in working it out according to the copy. 



104 



CHAPTER VII. 

BACK-LINING DRAWINGS. 

The following seven figures deal with the back-lining of draw- 
ings. The ordinary plan or elevation of an object often seems to 
the novice nothing more than a mass of lines, while, even to one 
experienced in reading drawings, some little study is necessary 
when dealing with the representation of a new object. A 
mechanical drawing, if left in outline and uncoloured, requires an 
expert to understand it, unless it is some very simple subject. 
There is nothing to indicate which parts are round and which 
are flat, which stand out and which recede, so that some 
acquaintance with the object represented is necessary to be able 
to **read" the drawing. A simple method of removing this 
difficulty is to "back-line" the drawing — that is, to thicken the 
outline on the shady side of all projections. This, however, has 
to be done by rule in order to obtain the greatest advantage from 
its use. 

For uniformity, the direction of the light is always supposed 
to come from the top left-hand corner, and to strike the paper at 
an angle of 45^. The arrow on p. 105 may be supposed to be a 
plan of a ray of light, and if one of the short sides of a 45*^ set- 
square be placed on this line perpendicular to the surface of the 
paper with the point towards the arrow-head, the long side of 
the set- square will represent the ray. 

If a solid, such as a cube, be supposed to stand on the paper 
in these rays of light, the sides nearest the top left-hand corner 
will be bright, and the opposite sides dark and casting shadows. 
"Wherever there is an edge casting a shadow, the line representing 
that edge is thickened. 

The examples shown in Figs. 169 to 172 introduce the projec- 
tion of plans and elevations from each other. If a simple body 
like a cube of 2-in. side, is placed in front of the eye, with one 
side " full-face," then the elevation is seen ; to look down on top 
of it will show the plan, but there will be no diff'erence in the two 
views except a diff'erence of position. Upon the drawing paper 



BAGK-LINING DRAWINGS, 



105 



the upper part is used for elevations and the lower part for plans, 
the corresponding views being placed exactly one under the other, 
the corresponding points being " projected," or drawn with the 
peacil and square. 

Suppose the 2 in. cube to be cut into halves horizontally, and 
the upper half of the cube to be removed, and the lower half to 
be turned round so that a corner will be nearest the eye, and 
that a smaller cube — say i in. — be placed on the top of it in a 
similar position to that occupied by the cube in Fig. 169, then the 
elevation and plan will give the two views shown in Fig. 170. 
These should be carefully studied, and the meaning of projection 





Fig. 169. Fig. 170. Fig. 171. Fig. 172. 

Projections of Plans and Elevations of Rectangular Objects. 

tested by trying various points, and having recourse to other 
objects, if necessary, to illustrate the different appearances of 
plan and elevation. 

The next pair (Fig. 171) shows a cube in the same position as 
that in Fig. 169, but having the interior cut out by a hole 4 in. 
square made through it, as shown in the plan. In the elevation 
the hole cannot be seen, but its position can be indicated by 
dotted lines ; and this shows one advantage a drawing has over 
a picture : the inside of an object can be shown as well as the 
outside. 

In Fig. 172 the hollow cube is turned diagonally, so that an 
edge is presented in the elevation. By this time the construc- 
tion of the various figures will be pretty well understood, and 
they may now be drawn in pencil, all lines being thin. The 



106 PBAGTIGAL DRAUGHTSMEN'S WORK 

elevations of the diagonally placed figures must be projected 
from the plans to get the right width, and it is well to test the 
plans themselves to see that they are correct before drawing the 
elevations. The principle of the test is that in any rectangular 
figure the two diagonals are equal. In inking-in, the outlines 
may be made thin first, and then the additional thickness added 
on to the outside (that is, the side the shadow is), or the thick 
lines may be put in direct. The following rules may be given : — 
Lines representing surfaces casting a shadow should be thick; 
lines representing edges only casting a shadow should be medium, 
and all other lines thin. 

Eef erring to Fig. 170 in the elevations, the right-hand line of 
the small cube represents a surface as w^ell as an edge ; it is a 
surface edgeways and casts a shadow : therefore it is made thick. 
The under side of the large half-cube represents two edges and one 
surface, and casts a shadow ; therefore it is thick. The middle 
line and the right-hand line of this half-cube represent edges only, 
as the surfaces themselves are visible, and the lines are made a 
medium thickness between that of the thin and the thick lines. 
All the other lines of this figure are usually made thin. When 
any doubt exists, imagine the drawings to be solid objects and 
move the set-square over them. 

After the previous illustrations the following three figures will 
be comparatively easy,' as they illustrate only an extension of 
the same principles. They show the application of back-lining 
to curved surfaces. Fig. 173 being a cylinder. Fig. 174 a small 
cylinder on top of a larger, and Fig. 175 a cylinder with a hole 
through it. 

In Figs. 170 to 172 has been shown how relief is given to flat 
surfaces representing rectangular objects, but there are two 
lines about which some doubt may have been felt— the right- 
hand top edge of the lower part of the elevation (Fig. 170) and 
Uie same part of the elevation in Fig. 172. Although these lines 
are part of the boundary of surfaces in the shade, they do not 
strictly come under the definition of edges casting shadows, and 
are left thin. It will be observed that the back lines — or shadow 
lines, as they are sometimes called — are applied as if the object 
itself were moved on the paper in plan and elevation, whereas, 
in practical geometry, the rule is to consider the Object immov- 
able and the paper bent at right angles, between the plan and 
elevation, to receive the projections of the various points on the 



BACK-LINING DRAWINGS. 



107 



outline. The latter method must be followed when a systematic 
study of shadows is made, and then the shadows in plan are 
projected diagonally upward from the bottom left-hand corDor. 
The method shown in the series of illustrations (Figs. 173 to 175) is 
much simpler and more convenient. 

In Fig. 173 is shown a cylinder 3 in. long and 3 in. diameter ; 
in Fig. 174 a cylinder 3 in. diameter and IJin. long, with another 
IJ in. diameter and 14 in. long standing upon it ; and in Fig. 175 
a cylinder similar to that in Fig. 173, with a IJin. hole through 
it. The plans must be drawn first, each circle being struck from 









Fig. 173. Fig. 174. Fig. 175. 

Projections of Plans and Elevations of Curved Objects. 



the intersection of two centre lines, and then the elevations pro- 
jected from them. It is better to ink-in with all thin lines and 
to add the back lines afterwards ; they are then more likely to 
be correctly placed outside the outline. In the elevations the 
bottom lines represent surfaces, and cast shadows, so that they 
will be made thick. The right-hand lines represent edges only — 
that is, the extreme projecting parts of the curves — and cast 
shadows ; therefore they will be made of medium thickness and 
the remaining lines thin. In the plans the lines all represent 
surfac s, but only parts of the lines cast shadows. The thick 
lines require to be eased off into thin ones without showing any 
abruptness, an operation which requires some little skill. 

Instead of opening the nib of the compasses to make a thicker 



108 



PRACTICAL DRAUGHTSMEN'S WORK. 



curve, they should remain as for a thin line, and the centre should 
be shifted from the intersecting point of the two centre lines 
downwards to the right at an angle of 45°, about the hundredth 
of an inch, so that the drawing of a second half circle will give a 
thickening that dies off gradually at the opposite 45^. Repeating 
this about three times will give a line of the required thickness 
and properly eased off at the ends. The thicker line becomes 
tapering because the radius is virtually increased in the one 
direction only, remaining practically unaltered in a direction at 
right angles to the shifting centre. 

The difference between a projection and a recess are clearly 
shown in the difference between the inner circles of Fig. 174 and 






Fig. 176.— Cast Iron Grating. 

Fig. 175, the edge casting the shadow being thickened in each case. 
If much difficulty is experienced in producing neatly the curves 
with one side thickened, it will be found very good practice to 
draw, say, a dozen concentric circles, with i in. differences 
between the radii, and back-line them all. 

Geometrical solids, such as those showm in the last seven 
figures, are better adapted for illustrating principles than ordinary 
objects are, but they are not so interesting. But having learnt 
the method of back-lining, the knowledge can be applied to such 
drawings as it may be desirable to improve, without the labour 
of shading and colouring. Fig. 176 shows a small perforated 
grating of cast iron arranged in diagonal bars with lozenge-shaped 
spaces. The rim or frame of the grating is 1 in. wide, the bars 
J in. wide and 1 in. apart ; the thickness, not shown, is 4 in., and 
the over-all dimensions are 14 in. by 9 in. The illustration is to 
be re-drawn full size. 

Commence as usual with the border line, then take 9 inches 



BACK-LINING DRAWINGS, 109 

in the scale or dividers, and mark where to put the bottom line 
of the grating on the paper, allowing room for the headnig and 
statement of scale. Rule in this line with the T-square, measure 
the length so as to leave it central on the paper, and then put in 
the double lines for the 1 in. width of rim. Now draw diagonals 
across the grating from the iilside corners ; and on looking at 
the illustration it will be seen that these diagonals pass along the 
centre of two of the bars, and give the direction of all the others. 
It is very easy to go wrong, but if correctly set off, there will be 
exactly half-lozeages all round the outside, and the distance 
between the points will be exactly equal to the distance between 
the points of the whole lozenges in the interior. 

If there were bars in one direction only, very few would make 
any mistake in the measurements, but the bars crossing each 
other cause many to measure the 1 in. distance apart along one 
of the lines of the other set of bars, instead of at right angles to 
the bars which are being set out. At first sight it may appear 
that the dimension 1 in. between the bars near the centre of the 
illustration is twisted out of place ; it is, however, correctly 
placed, and shows the direction in which the measurement must 
be taken. Being full-size, the drawing does not require a scale 
at the bottom, but the dimensions should be figured in, as they 
establish the precise size required, and to some extent render the 
work independent of the accuracy of the drawing. 

In most specifications of work to be done, a clause is inserted 
stating that — "Where any discrepancy exists between the scale of 
a drawing and the figured dimensions, the latter are to be worked 
to, unless obviously incorrect." When the back-lines are put 
outside the solid parts, accurate measurements can be taken from 
the drawing with as much facility as if all the lines were thin ; 
but to be useful, this rule must have no exception. If the bars 
in the illustration had been at an angle of 45°, instead of about 
30°, as^t present, only those going upwards from left to right 
would be entitled to back-lines, although generally the others 
' w^ould have them also for the sake of effect ; in that case the 
lower sides of the other bars would receive the back-lines, 
although having no more right to them than the upper sides. 

Owing to the thickening up of the thin lines unavoidable in 
printing, there may be some doubt, in looking at the illustration, 
as to which lines are there intended to be back-lined ; but if the 
grating be looked upon as an actual object resting on the paper 



no 



FEAGTIGAL DRAUGHTSMEN'S WORK 



with the light shining down diagonally from above the top 
left-hand corner, it will be evident which lines would cast 
shadows. 

Reversing the type of illustration given in Fig. 176, a cover- 
plate of the style known as '* chequered," for placing over an 
opening such as a valve-pit, manhole, etc., may be drawn. The 
chequers, or raised pieces, are to prevent slipping, and give a firm 
foothold when passing over it. In this case only one corner of 
the plate is shown on the drawing ; the remainder being appar- 
ently broken away. This is a method frequently adopted in 
drawings when there is much repetition work about the object, 
and the drawing is desired upon a large scale. The outside 



- -^ Q^'OVET! 




SECTION 
ON UN? TtB 



Fig. 177.— Chequered Plate. 



dimensions fshow that the whole plate is 3 ft. 9 in. by 2 ft. 11 in., 
and calculation will show that this will allow for six chequers in 
length and eight in width. Another method sometimes adopted 
is to show the outline of the whole plate to a small scale, with a 
few of the chequers in one corner, and perhaps a single chequer 
full-size with the dimensions to it. 

A section is the surface exposed by an imaginary cut, and the 
** section on line A B " shows the surface that would be exposed at 
that particular part. The hatching or diagonal lines show the cut 
surface, the projecting parts on the left being the chequers that 
are cut through, and the light parts between them, the ends of 
the other chequers seen in the distance. The chequers stand out 
Y*^ in., the total thickness being 1 in. 

In making this drawing (Fig. 177) commence with the top line, 
and follow with the left side ; set off the width of rim or plain 
edge, then divide the inner edge of left-hand side all the way 
down according to the dimensions given, bearing in mind the 



BACK-LINING DRAWINGS. Ill 

required scale. Then with the 60° and 30^ set-square, set ofi the 
projecting points or half-chequers, and see by the T-square that 
they all come in line. 

From this stage onwards there are various methods of work- 
ing ; perhaps, on the whole, the following will be the best : — 
From the inside of the rim draw horizontal lines 1 in. apart (to 
the scale required), and vertical lines Ij in. apart, similar to the 
few that are shown by dotted lines on the illustration. Then by 
joining the proper intersecting points as many chequers can be 
drawn as may be desired, and the lines rubbed out after the 
chequers are inked in. When part of the figure is broken away, 
there is no precise limit — that is, half a chequer more or less in 
either direction makes no difference. Pat on the "line of sec- 
tion," A B, and then draw the section, observing that all points 
of the section correspond horizontally with all points on the 
line A B. 

This drawing should be back-lined similarly to Fig. 176, but 
the lozenges being now projections instead of recesses the back- 
lines will be reversed. Upon a comparison of the two illustra- 
tions (p. 108 and p. 110) it will be seen that back-lining a drawing 
not only gives relief and variety to it, but helps also to explain 
the shape of the object represented. 

The two following illustrations show a method of indicating 
the proportions of a structure by multiples of some unit. The 
unit in this case is the depth of the fillet in the base moulding of 
the pilaster (Fig. 178). A pilaster differs from a column in being 
a flat projection from a wall instead of a detached cylindrical 
construction, although both may be of the same general style 
and character. The size of the drawing depends upon the size 
adopted for the unit, which may here be one-eighth of an inch. 
By taking a larger or smaller length for the unit, the whole 
design will be proportionately enlarged or reduced without affect- 
ing the relationship of the parts to each other. Very much the 
same thing may be done by measuring a drawing with the wrong 
scale, and reading all the dimensions larger or smaller, as the 
case may be, from which the new drawing is constructed. The 
work given in Figs. 178 and 179 will be a very good test of ability ; 
it requires a good eye and a steady hand to produce some of the 
parts, as any irregularity will be easily detected. 

Begin with the plan of the pilaster (Fig. 178) and note that 
any measurements re( quired which are not on that view may be 



112 



PRACTICAL DEAUGHTSMEX'S WORK. 



found on the elevation. The section line- in the plan show that 
it is, as plans very often are, a sectional plan — that is, not taken 
as it would appear when looking down above the sumnait of the 
structure, but from some intermediate height. The mitres in 
the plan at the external angles are produced by the junctions of 
the straight mouldings. The bottom of the plinth is not back- 
lined, because it would of necessity stand on something of larger 
area, and that would prevent a shadow being cast : it is shown 
standing on the ground. The semicircular flutings in the pilaster, 



v^ v^ U w LJ 



1 } 

; ' BASS 




WmmF ''''----''^''- '■'■<^^''''>^<^y mm^. 



^.r-r-<r--.r--.r-- 



Fig. 178.— Fluted PHaster. 



4 units wide, are separated by narrow fillets, or flat surfaces 1 
unit wide, and they are terminated at each end in the elevation 
by semicircles. The lower end only is shown, for want of space. 

The column (Fig. 179) has similar flutes, say twenty in all, 
round the whole circumference, which will make it about 32 units 
in diameter. These should be set off in the plan and projected 
into elevation. At this point a great difference will be seen as 
compared with the pilaster (Fig. 178), although the flutes are in 
reality the same size, they are foreshortened, or turned sideways, 
towards the sides of the column, and appear much closer. This 
involves a special difficulty at the lower end of each flute, wherQ 



BAGK-LINING DRAWINGS. 



113 



the semicircle will become elliptical, with one axis shortened 
more and more. The semi-ellipses will be all the same height as 
the semicircle, and the width will be given by the projection 
from plan. The curves themselves must be drawn very neatly 
by hand, so that their outline may be precisely similar to the 
other outlines. Sometimes an expert draughtsman may be found 
who can put them in with the bow-pen, but generally, if instru- 
ments are used, the curves will be steady and uniform, but badly 
shaped, while if put in by hand the curves will be unsteady and 
irregular in thickness, but better-shaped. In back-lining this 




MALf PLANJ 

Fig. 179.— Fluted Column. 

drawing, observe that the thickening of the curves is regulated 
by the 45*^ set-square, which shows where the line alters its 
character. 

. It should be remembered that, although the illustrations 
are printed when they appear in this book, yet they were all 
originally drawn by hand, and that any difference of quality is 
in favour of the original ; every effort should therefore bo made 
to make drawings at least equal to the copy from which they are 
taken, and then good substantial progress may be expected. 



lU 



CHAPTER VIII. 

DRAWING TO SCALE AND PREPARING MAPS. 

Mechanical drawings are usually made to a given scale, 
regulated by the relative size of the drawing paper as com- 
pared with the object to be represented, and it will be under- 
stood at once that only comparatively small objects can be 
drawn to actual size, as the draughtsman is limited by 
conditions of space and by considerations of convenience 
in handling. For example, in plans of buildings, maps, 
surveys, and in fact the great majority of the instances 
in which drawing is employed, it becomes necessary to 
reduce the representation of the object. In cases of minute 
mechanism it is desirable to increase the scale of them so 
as to show construction clearly. 

The scale of a drawing is the proportion the representation 
bears to the actual object. A drawing is said to be "to scale," 
when all parts are in strict proportion to the original ; and even 
rough sketches should be approximately to scale, or they will 
give a distorted representation which may convey a wrong 
impression. When a drawing is made to the same size as the 
object represented, it is said to be full size, while, if all the 
dimensions of the object are represented by distances on the 
drawing that are half full size, the drawing is said to be half full 
size. Since ordinary working drawings represent surfaces, not 
contents, the representation of an object with its length and 
breadth each reduced to, say, half the full dimensions would really 
be quarter full size regarding area represented. Lengths, not 
areas, are, however, measured, and the drawing is said to be half 
full size. 

When it is proposed to produce a drawing of anything 
that measures more than two or three feet across, the draw- 
ing must almost of necessity be smaller than the object ; and 
in order that the object may be reproduced faithfully, the 
reduction must be in every way proportionate. To whatever 
extent the representation of the object is diminished or in- 



DRAWING TO SGALHJ AND PBEPABTNG MAPS. 115 

creased, the relative proportion of every part of the drawing 
to the corresponding part of the object must remain uniform 
throughout in order to produce a working drawing. In 
constructing a drawing either to a smaller or larger scale 
an artificial scale of measurement must be provided which 
shall bear the same relationship to standard length as the 
drawing is to bear to the real object. 

The scale of a drawing, then, is the proportion lengths on the 
drawing bear to lengths on the object, and if a drawing measured 
3 in. in any dimension, and it were known that that dimension as 
measured on the object was 1 ft., the scale of the drawing would 
evidently be 3 in. = 1 ft., or fV = i full size. All drawings, even 
when fully dimensioned, should have the scale stated, preferably 
under the title or heading, and if a detail, to show it more clearly, 
is drawn to a larger scale, the new scale should be mentioned 
near the detail drawing. 

Scales are named according to the fraction they represent 
of the object to be drawn. For mechanical and building 
drawings, the following scales are generally used: — 3 in. to 
a foot (Fig. 180), 1^ in. to a foot, | in. to a foot (Fig. 182). 
These scales are popular in the workshop, because they may 
be measured conveniently with an ordinary mechanic's rule ; 
i in., J in., and yV ^^- representing 1 in. on the first, second, 
and third scales respectively. Again, 1 in. to the foot 
(Fig. 181) would be yV ^^ ^^e full-sized object, and the scales 
would be known as ^2, and so on. This method of naming 
the scales is general for students' work, but in the workshop 
the prevailing practice is to call the above scale " inch'' 
and others '^ inch and a half," etc. 

The scales shown in the accompanying examples are not repro- 
duced to the full size marked upon them, owing to considerations 
of space ; they should therefore be drawn again for use and 
practice. As an example, the construction of Fig. 180, a scale 
Sin. to lft = i, will be described. Three feet to this scale are 
shown, but the limits to which the scale is to be set out must 
depend on circumstances. Commence by drawing two lines 9 in. 
long and about y\ in. or i in. apart. Divide this length into 3-in. 
parts, each of which will represent a foot. The first division 
should then be further divided into twelve equal parts, each y\ in. 
or Jin. long; these represent inches, and may be subdivided 
into half inches and quarter inches, the latter dimension on this 



116 PBAGTIGAL BUAUGHTSMEN'S WOBK 

1 
scale being represented by a length of-i^^^^in. The first foot, 

divided as just described, should be marked off in lengths of 3 in., 
as shown, starting with 12 in., and working forward to Oin. The 
other divisions on the scale may be left open, as shown. The 
scale may be completed by drawling lines close to the top and 
bottom lengths, with alternate divisions marked by thick central 
lines, as shown (Fig. 180). 

i^zztle - 3 inches to 1 foot = ? 



INCHES 12" © 6 3 o 

[ u< U-i t-J i-i -Mr-f=j- 



Fig. 180.— Quarter Scale. 

There is a special reason for numbering the feet forward 
and the inches backward as shown. For instance : to measure 
1 ft. 9 in., or X 9", open the compasses from the division marked 
1 ft. to the division marked 9 in. If the inches had been marked 
in the same direction as the feet, and the feet had commenced at 
the left-hand end, as they are sometimes carelessly set off, then 
the scale would be found very confusing to measure from. It is 
better to number the inches 3, 6, 9 and 12 only than every one. 



Fig. 181.— Twelfth Scale. 

The proportion between the length of 1 ft. on the scale and 
1 ft. of the actual object gives the ratio of the two things, and, 
stated as a fraction, gives the representative fraction. In the 
case of 3 in. to 1 ft. the representative fraction is J. This is 
always "^vX on foreign drawings, so that the proportion may be 
understood by anyone unacquainted with the language ; but on 
English drawings it is not generally found. It will be observed 
that the thick lines through the centre of the scale, are placed in 
alternate spaces. The first foot divided into inches is naturally 
heavy looking, so call this dark ; then the next foot from to 1 
will be left light, and 1 to 2 will be made dark, and so on ; then 
backwards in the same way with the inches dark and light 
alternately. 

The next scale shown (Fig. 181) is suitable for larger objects or 



DRAWING TO SCALE AND PREPARING MAPS, 117 

for smaller drawings, the scale being generally selected according 
to the size of the object ; it is set off similarly to the last, making 
it 6 in. long altogether, and dividing the first foot into inches. 
It may be marked off easily from a scale with twelfths of an inch, 
or the following construction may be readily adopted : At the 
commencement of the scale draw a line at an angle of, say, 30^ to 
45^ ; take the dividers and set them rather less than |- in. apart, 
then along this line prick off twelve divisions ; join the last one 

Scale ^ ^4 i/ich to 2 foot = 43 

Fig. 182.— Forty-eighth Scale. 

with the end of the first foot, and from the other points draw 
lines parallel to this one, which will give the twelfths of an 
inch required on the scale. 

In the next example (Fig. 182), i in. to 1 ft., the smallest 
dimension that can be conveniently marked is 3 in., so the first 
foot can be divided into four parts only, and in the final example 
of 10 ft. to 1 in., only feet can be shown. These will want extra 
care, and a fine point to the pencil. Fig. 183 shows a scale of 
1 in. to 10 ft. 

ScaZe « JO feet to I inch = Teb 

lO 5 o lo 2o so *o SO 

fe prg-R kJ I _[ ' " I., ., J • - j 

Fig. 183. — One-hundred-and-twentieth Scale. 

Cardboard scales containing all the divisions generally 
required can now be obtained so cheaply that many scarcely 
ever use any others, but persons who have to work with them 
constantly prefer boxwood, while those who can afford it 
obtain ivory scales, because they are clean and lasting and, 
what is of more importance, their divisions are generally 
more accurate. For ordinary purposes a drawing will be 
good enough if constructed by such a scale, and the size 
written on, as 3 in. to 1 ft., or whatever the proportion may 
be between the drawing and the real object; but, for very 
accurate work, such as civil engineering or ordnance survey 
work, the scale should be constructed, or copied line for line, 
at the foot of the drawing, so that, as the paper shrinks or 
swells with the weather, the scale will vary exactly as the 
drawing does, and be a true measure for it. 



118 FRACTICAL DEAUGUTSMEJS 'S WOBK. 



n ? p 

I ' 

u 
u O 

o y 
u 

u i^ ( 
< CO 

o 

u> a: 
o 



.)-I 



-J 



|0 2 



O ^ 

UJ 5*- O 



tn 



It 
O 



fee 



1 



r3 
O 






tn 
O 






bo 



DRAWING TO SCALE AND FEEPAEING MAPS. 119 

In working drawings of great importance it is usual to make 
a scale on the lower border line before commencing the work, so 
that the atmospheric changes may affect the drawing and the 
scale equally ; but in ordinary work the scale is made after the 
drawing, simply for the purpose of ensuring that it is always at 





Fig. 186.— Square. Fig. 187.— Circle. 

Examples of Scale Drawings. 

hand when the drawing is in use. These scales are made with 
slight variations according to their size, which will be evident 
on comparing the various illustrations given in this book as 
examples. 

The correct method of plotting a scale upon a drawing 
may be illustrated by the accompanying examples, Fig. 184 



11 









/*^i 




^^^''^iv^^^'t^^^.J^'ol 



C^ 



■TilM-/^ 



Fig. 188.— Sketch Plan of a House. 



showing a scale plotted to J in. to a foot, and showing a length 
of 70 ft., and Fig. 185 a scale plotted to 2^ 5V0 (Ordnance scale), 
showing a length of 2,000 ft. Each scale should be plotted 
with, a fractional part on the left of zero, so that distances 
like 23 ft. on the first scale and 375 ft. on the second scale may 
be measured by placing the dividers on the respective figures. 
The accompanying scales are reduced to half size for printing. 
In addition to scales, a square (Fig. 186) and a circle (Fig. 187) 
are shown, and as an exercise each is to be drawn to the scale 



120 



PRACTICAL DRAUGHTSMEN'S WORE. 



mentioned upon it. Scales in common use for architectural 
drawing are i in. and i in. to 1 ft. for plans, elevations, and 
sections, and fin., 1 in., li in., and Sin. to 1ft. for details, and 



1^ -rS' /6 




Fig. 189. — Diagonal Scale for Accurate Measurements. 

full size for mouldings. In machine drawing, iin.^ 1 in., Hin., 
and Sin. to 1ft. for general plans ; IJin. and Sin., half size and 
full size, for details. In other branches smaller scales are 
common, as 100 ft., 50 ft., 40 ft., 20 ft., and 10 ft. to 1 in. in civil 



108 6 4 2 O 





nizzjizz 










2 


^ ± :± : 










; ±... .- 










4 












I ixiiiii 










6 


r — T 










r" 1 










8 


^ 










/ 










10 


\±LJ'JJ-L 











Fig. 190. — Scale Showing Tenths and Hundredths. 

engineering ; 88 ft. to 1 in., S chains to 1 in., etc., in land survey- 
ing. Sometimes, in order to get an even representative fraction, 
some peculiar scales are used for maps — for example, 25*344 in. 
to 1 mile is used because it gives the representative fraction of 
2-\jo, as shown in Figs. 185 and 19S. 

Drawings that often come under notice include plans of 
houses. These are generally drawn yV of full size — that is, 
on a scale of J in. to 1 ft. Upon this scale it is possible to 
show the size and shape of every room, the position of every 
door, fireplace, and window, stairs and landings, slopstone, 
gully, bath, water-closet, cupboard, down-pipe, gutter, etc., 



DRAWING TO SCALE AND PREPARING MAPS. 121 

etc. A drawing of this kind, with all the thicknesses of 
walls, etc., shown accurately, takes some time to produce; 
but for note-taking elaboration is hardly necessary ; but a 
rapid sketch of a house, as shown at Fig. 188, would be 
intelligible to anyone familiar with buildings. 

Plans of land are drawn to a small scale, from which the 
inch marks are necessarily omitted, and in w;hich the feet, 
when they are represented at all, have their ciphers left out. 
For large tracts of land a scale of 6 in. to the mile is often 
used ; for smaller portions, a scale of 1 in. to a chain is 
commonly employed. 

In cases, where fine divisions are required, the diagonal 
scale is generally adopted. In drawing one for the first time, 
it is better to make it a large one, as then the construction 
can be followed more readily ; say, the illustration shown by 
Fig. 189 is first drawn with 5 in. for the unit. The division 
of the first space on the upper line into ten equal parts may 
be made by stepping ten times with the spring dividers, or 
geometrically, as shown, and must be repeated at the 
bottom. Similar divisions are then to be made on the left- 
hand vei-tical line, all the horizontal lines drawn through, 
and the vertical lines at each 5 in. The diagonal lines must 
next be put in, the first of them reaching from zero on the top 
line to the end of the first division on the bottom line, and 
the others parallel to it, so that, as each diagonal crosses a 
horizontal line, it leaves a space increasing by hundredths 
of the unit. 

In the third line down will be found two small circles, 
the distance from centre to centre being 1'62, measured thus : 
on the right from the zero line is one unit, the sixth diagonal 
line on the left from the zero shows six-tenths, and the second 
line down from the top shows two-hundredths contained 
between the zero line and the first diagonal. The two circles 
in the third space from the bottom represent 1*375, being 
midway between 1*37 and 1'38. The smaller scale, illustrated 
by Fig. 190, is like those that appear upon the machine-made 
scales, and will now be understood without further descrip- 
tion. 

In the case of a map or plan, for example, the artificial 
scale may have an actual length of, say, 5 in., which at the 
same time represent a distance of ten miles in the drawing. 



]22 PRAGTIGAL DRAUGHTSMEN'S WORK 



In this instance the scale would be divided into ten equal 
parts, each indicating miles, while by subdividing one of 
these divisions into eight equal parts, furlongs would be 
represented. Here an actual length of half an inch is under- 
stood to represent one mile, and the map or plan would be 
described as being drawn to a scale of half an inch to the 
mile. Another way in which this fact may be stated is 
this: — The number of half inches in a mile is 1760 X 3 X 
12 X 2 = 126,720 ; and as this number of half-inches is repre- 
sented by one half-inch, it is evident that the drawing is 

m 







Fig. 191.— Scale -^^ho ' 1 in. = 880 ft. ; 6 in. = 1 mile. 

only 72 6V2 o the size of the real object it is intended to show. 
This sum y26V2^ ^s known as the representative fraction of 
the scale, and sometimes is used to indicate any particular 
scale instead of the previous expression. 

The value of scale drawings is particularly shown in the 
maps issued from time to time by the Ordnance Survey. 
These have not all been drawn to one uniform scale, it having 
always happened that before the map of the whole country 
could be completed upon any one scale, the discovery of some 
defect or the suggestion of some improvement has induced 
the Department to begin afresh upon a different scale. 



BBAWING TO SCALE AND PEEPAEING MAPS. 123 

Speaking generally, the whole country has been mapped 
out upon a scale of 1 inch to the mile, and also on a scale 
of 6 inches to the mile (see Fig. 191). Maps on this scale 
are too small to represent anything but the barest outlines 
of very large schemes, and here they need not be further 
described. 




Fig. 192.— Scale i^Ve : 1 in- = 88 ft. ; 10 ft. = 1 mile. 



Later, the Department issued maps of the principal towns 
on a scale of 10 feet to the mile, or 1 inch to 88 feet (see 
Fig. 192), This map, though small, was very useful. It 
was very clearly printed from engraved plates, and was a 
work of art as compared with the maps issued at the present 
time. This scale, however, has been abandoned, and the 
Department now publish town maps on the following scales 
—namely, 25^344 inches to the mile, or 1 inch to 208'33 feet 
^^ Woo full size (Fig. 193), and 10*56 feet to the mile, or 
1 inch to 41-06 feet, or ^l^ full size (Fig. 194). This last 



124 



PR ACTIO AL DRAUGHTSMEN'S WORK. 



map is exceedingly useful, the scale being large enough to 
show upon the map man-holes, sewer ventilators, gullies, 
lamps, etc. ; and by its aid can be laid down schemes for the 
drainage of even a single house. The sheets of these maps 
measure about 38 inches by 25 inches, and can be purchased 
plain or coloured. 

The accompanying illustration shows a small portion of 




Fig. 193.— Sca^e ^^^-^ : 1 in. - 208-33 ft. ; 25-344 in. ^ 1 mile. 

the -Qjio Ordnance map. At the comer of the house a bench 
mark has been cut (these are usually about 1 ft. 6 in. above 
the surface of the ground), and the figures indicate that the 
point is at a height of 89'55 ft. above Ordnance datum. The 
Ordnance datum is an imaginary horizontal plane extending 
over the whole country at the same height as the ^average 
mean level of the sea at Liverpool. This datum was fixed 
by the surveyors of the Ordnance Department, and the levels 
of districts are marked on the Ordnance maps as being so 
many feet above the Ordnance datum ; that is, above the 
average sea-level at Liverpool. The figure in the roadway 
indicates that the road at that point is about 877 ft. above 
the datum, the second place of decimals not being given. 



DR AWING TO SCALE AND FREPABING MAPS. 125 



Figs. 191 to 194 illustrate plans of streets, and these 
drawings show what the street would look like as seen from 
a balloon. All these are drawn to scale so that the lengths 
and widths can be measured from the plan. Kerb-lines are 
usually represented by dotted lines. Ordinary colours used 
for the roadway are sepia or pale indigo ; footpaths, pale 
burnt sienna ; buildings, crimson lake or indigo. Lines of 
sewers are shown by blue lines or thick black lines. 



0^^ ^ 



Q 
Co 






Fig. 194.— Scale 



1 in. = 41-66 ft, : 10'56 ft. = 1 mile. 




A drawing showing what the street would look like if all 
one side of the street were excavated away, the spectator 
looking squarely at the face of the excavation, would be 
called a section. The drawing would then show the setts at 
the top, the ballast underneath, earth beneath that again, 
and, lower down still, the gas and water mains and sewers. 
In sections for new streets that are to be made, the present 
surface of the ground is indicated by a more or less crooked 
line. The finished level and the formation level are gener- 
ally indicated by coloured lines, and the sewer is shown at 
its proper depth and inclination. 



126 



CHAPTER IX. 

COLOUEING DRAWINGS. 

Colour is a very considerable aid to '^ reading " a drawing, 
particularly when different materials occur adjacent to each 
other. Architectural and mechanical drawings are intended 
for use rather than for decoration, and the colouring is used 
chiefly to denote the different kinds of material, but there is 
no valid reason why a drawing should not be neatly finished 
as well as accurate in draughtmanship and colouring. The 
colours not only emphasise the separate pieces by contrast, 
but custom has decided that certain materials shall be repre- 
sented by certain colours, some being almost the natural 
tint of the material, and others purely conventional. It is 
more important that parts in section should be coloured 
than parts in elevation ; a section is always an imaginary 
cut, and the colour is put upon the cut surface because other- 
wise it is not so easy to recognise as it would be in the 
elevation. A true section can be seen only by '^ mental 
vision," while an elevation is subject to ordinary vision. 
The list on p. 138 gives selections from the practice of the 
best engineers' and architects' offices, and is the standard 
adopted by many. Some of the colours may be replaced 
by less expensive ones, such as yellow ochre for Roman 
ochre, neutral tint for Payne's grey, or neutral tint with a 
little crimson lake for violet carmine. 

The extremes of good and bad drawing and colouring 
are commonly to be found in architects' oflices as contrasted 
with civil engineers' work. Some of the faults are running 
all lines beyond the proper junction, making them also 
unnecessarily broken and very thick, ruling ink lines close 
above and below and even through the printing, making 
letters of such fantastic shapes that reading is difficult, and 
even extending the same style to the dimension figures, 
using crimson lake in colouring elevations instead of one of 
the numerous reds having the natural tint of red bricks or 



GOLOVRIJSTG DRAWINGS. 



127 



tiles, using Prussian blue for anything but wrought iron, etc. 
A detail drawing sent out from an architect's office, that 
showed a wrought-iron girder resting on a cast-iron column 
standing on a stone base, had all the parts coloured with a 
full tint of Prussian blue on the score of custom, so that the 
use of colour at all was of no advantage whatever in dis- 
tinguishing the material ; moreover, Prussian blue is a harsh 
colour at the best of times, and should be avoided whenever 
possible. Many draughtsmen have a natural talent for 
using suitable colours, and putting them on in a suitable 
manner, but others must go through the drudgery of careful 




Fig. 195. — Slant and Saucers for Colours. 



practice according to rule. A perfectly uniform tint such as 
desired on an engineer's drawing is not required on an 
architect's drawing, and still less on that for use by a 
builder ; but unless the draughtsman learns first to lay on 
a flat and uniform wash of any tint, he is not likely to be 
able to put on an appropriate rough tint. For water-colour 
sketching a flat tile with shallow recesses is suitable for 
mixing the colours, but this is quite unsuited for a draughts- 
man's use. He should invariably use the nests of round 
saucers fitting one on the other, as shown by Fig. 195, of a 
size to hold as much colour as would be required to com- 
pletely finish the colouring of any one material on one sheet. 
The saucers should be kept covered while in use, and washed 
out when done with. The lightest tints should, as a rule, 
be put on first, and the brush should always be of ample 
size. Colour brushes should be kept scrupulously clean, 
never put in the mouth, always washed after using, the sur- 



128 



PR AG TIG AL DRAUGHTSMEN'S WORK, 



plus moisture shaken out, and then put away in the box and 
not laid on a dusty shelf to dry. 

In giving on p. 138 a list of the colours used in architec- 
tural and mechanical drawings, it may be said that the 
colours adopted vary according to cuxumstances, and it is 
difficult to lay down general rules. The practice in some 




Fig. 19G. — Primary Colours and Secondary Tints. 

good offices is to use a very pale sepia for York stone in 
elevation, pale Payne's grey for Portland or Bath stone, 
pale indigo for granite with ink dots, and darker tints of 
the same colours for the sections. Architects, who ought 
as a body to have an eye for colour, sometimes offend by 
using harsh and unnecessary colours on their drawings. 



COLOURING DRAWINGS. 129 

Blue in some form or other is much used by architects to 
represent stone, but it should be used very sparingly, so as 
to resemble the natural tint of the stone rather than the 
conventional representation. For a red sandstone, a pale 
tint of light red, Indian red, Venetian red, or burnt ochre 
might be used, depending upon the general elevation colour. 
For cement in any form in elevations, pale Indian ink or 
pale Payne's grey is generally used, with or without dots 
and markings. Windows may be coloured with black 
Indian ink, or washed Prussian blue, Prussian green, or 
Payne's grey, according to circumstances. A plain tint all 
over is the simplest, but a good artistic effect may be ob- 
tained with the exercise of a little skill. 

A little practice in the laying of colours one over another 
will be useful for impressing on the memory the general 
effect of combination and also a knowledge of the primary 
colours and their secondaries. Nearly all water-colours 
are transparent, and a medium tint of any one colour, if 
laid over another after it is dry, will allow the first colour 
to show through. A more intimate combination may be 
made by mixing the colours together in the same palette 
and putting them on with the brush in one operation. 

It should be noted that a draughtsman never speaks of 
^' painting " his drawing ; the term is frequently misused, 
but it should be colouring or tinting. 

If a circle (Fig. 196) and a square (Fig. 197) be set out and 
coloured as marked in the accompanying diagrams, some of 
the results of combination may be easily produced. Prepare 
in separate saucers some Prussian blue, crimson lake, and 
gamboge to medium tints of about equal intensity ; these 
are the so-called primary colours. In Fig. 196 the half-circle 
marked purple, red, and orange should be coloured first with 
a tint of crimson lake ; as soon as it is dry the half-circle 
marked purple, blue, and green should be covered with a 
tint of Prussian blue ; and the half- circle marked orange, 
yellow, and green should be covered lastly with a fairly 
strong tint of gamboge. Where the pairs of colours are 
superposed, the secondary tints of purple, orange, and green 
will be found to have been made by the combination. Each 
section of colour in the circle will be complementary to 
the one opposite it — that is, it will be in extreme contrast, 
I 



130 



FRAG TIG AL DRAUGHTSMEN'S WORK. 



and it is a physiological fact that when the eye is fatigued 
by looking at one of them it will be rested by looking at that 
opposite. 

If a square of 7 in. side be divided into parallel columns 

VIOLET INDIGO BLUE CREEM- YELLOW ORANGE RED 




Fig. 197. — Colours of the Spectrum, 



Oi 1 in. each and numbered as shown in Fig. 197, and equal 
tints of crimson lake, indigo, Prussian blue, and gamboge 
be prepared, the various rainbow colours named upon the 
columns may approximately be produced as follows : Tint 
the columns numbered 1, 6, and 7 with crimson lake, 1 and 2 
with indigo, 3 and 4 with Prussian blue, and 4, 5, and 6 with 



COLOURING DRAWINGS. 131 

gamboge. The lines drawn across the diagrams show the 
extent of each colour. If care be taken to put on even tints 
and not to go beyond the outline, this recreation of colouring 
will enable the practical work to be carried out efficiently. 

In practical colouring for draughtsmen's work (see Fig. 
197) the first point to note is that the colour in any one space 
must not overlap the boundaries; it must be of the right 
tint, and laid on perfectly flat or uniform. To do this re- 
quires skill that can only be acquired by practice. Use a 
set of colour saucers, in one of them put a little clean water, 
but not much, as a teaspoonful will colour a square foot ; 
rub in it gently the end of a hard-cake colour, until it is dark 
enough, and then stand the colour up on its dry end. Use 
a brush about J in. diameter and | in. long, rinse it in clean 
water, and pass it through the saucer to mix the colour until 
it looks perfectly uniform, without points or marks near the 
edges, end above all without chips in it. 

Wipe the brush lightly on the edge of the saucer to remove 
the surplus colour, and hold it as described for a lead pencil 
when about to draw a vertical line ; commence at the top 
left hand of the space to be coloured ; pass the brush down- 
wards, then along the top, then down by short strokes from 
the top to the length of the first stroke, and so carry the 
colour downwards for the whole width, finishing at the 
bottom right-hand comer. 

To produce good and uniform colouring, never damp the 
paper before coromencing, re-fill the brush often, gently 
wiping it on the edge of the saucer each time. The margin 
of the colour must not dry before the next stroke reaches 
it, and a part once coloured must never be retouched, even 
though it looks uneven. Retouching is a fruitful source of 
failure ; for colour, looking uneven when wet, may dry even, 
but if touched again when partially dried it is certain to show 
uneven when dry. 

' There is an advantage in having plenty of colour in the 
brush, but when nearing the bottom boundary the amount 
must be reduced, so that there is not a pool left at the lower 
corner. By regulating the amount of colour any slight 
excess may be picked up with the brush by simply raising 
it slowly, point last, from the corner. The brush should not 
be wiped in any way, but simply washed in clean water when 



132 PBAGTIGAL DRAUGHTSMEN'S WORK 

done with, or before use with another colour. It will soon 
be found that with a given amount of colour in the brush 
more or less of it may be left behind as the brush is allowed 
to trail or is used sideways, and it is by unconscious adjust- 
ments of this kind that a good colourist produces uniform 
results. 

It is useful to remember that sections of materials are 
always coloured with a dark tint, but the term dark is only 
relative ; for instance, with dark Prussian blue for wrought- 
iron, it should be quite easy to read ordinary dimension 
figures. Dark tints are more difficult to lay on evenly than 
light ones, but the same method is adopted. Another source 
of difficulty in sections is that to produce the best results a 
very narrow white margin should be left uncoloured on the 
top and left of each portion, where rays of light from the 
top left-hand comer of the paper would strike upon them. 
This custom enables the number of plates to be more readily 
seen in large girders, and makes all sections more effective. 

The colours for tinting woodwork on a drawing may either 
be plain, or, if time and other circumstances permit, may 
be laid on in imitation of the natural grain, although, to a 
certain extent, all colouring on mechanical and architectural 
drawings is conventional. For the plain tints the following 
may be used : Fir and deal used in the rough, raw sienna 
or gamboge ; for the same if wrought and for pitch pine, 
burnt sienna ; for oak, burnt umber or sepia ; for mahogany, 
light red. If graining is to be attempted, each kind of wood 
requires three gradations of colour for elevation and section. 

Suppose an example be attempted of wrought fir or deal 
as in the accompanying diagram, a pale tint of burnt sienna 
must be laid uniformly over the front and side elevations 
(Figs. 198 and 199), including the splintered ends, then a 
darker tint must be mixed and laid uniformly over the end 
grain and cross-section pieces. This darker tint will be the 
one used for the graining on the front and side elevations, 
and in mixing this colour it would be well to compare a 
piece of the actual wood represented, as the accompanying 
illustration, as printed, is necessarily much too black to give 
the right effect. Two brushes will be needed, one for the 
colour and one with plain water for softening the inner edge 
of the graining lines as they are put on. The water brush 



GOLOUEING DRAWINGS. 



133 




Fig-. 201.— End Grain, 



134 PRACTICAL DRAUGHTSMEN'S WORK. 

should be wiped on the edge of the glass or gallipot con- 
taining clean water, leaving the brush wet, but not fully 
charged, and every minute or two it must be rinsed in the 
water to keep it clean. 

The so-called heart part in a board showing good grain 
appears in wider pieces than the other part, and more filled 
up at the ends, while the grain towards the edge appears 
narrower and in lines closer together. The heart grain also 
gets more and more pointed as it leaves the central piece, 
until it runs out into nearly straight lines or widens again 
into a fresh piece of heart. The outer edge of the graining 
in elevation should be sharp and clear,^while the inner edges. 




Fig. 200.— End Grain. 

should be softened off with the water brush in a graduated 
tint, so that it shall be difficult to see where the colour ends. 
In doing this, care must be taken not to overlap the sharp 
edge of the inner line. It is rather better to work from the 
middle of the board outwards than to put in the outer grain 
first. In the side elevation (Fig. 199) the grain is shown 
by single lines slightly waved, and all softened on the lower 
edge. 

The elevations having been complet-ed, the colour should 
now be mixed in its third degree of intensity for the parts 
showing end grain or cross section (Figs. 200 and 201). No 
distinction is made between these two conditions. The rings 
showing the annual growth of the tree may be lightly pen- 
cilled if desired, but it is just as well to proceed at once with 
the colour, making the rings dark on the outer edge, and 
softening the inner edge with the water brush. After the 
rings are dry, about three radial lines may be put in at 



GOLOUBING DBAWINGS. 135 

random without any softening. These may look like heart 
shakes, but they are really to give more effect and to relieve 
the monotony of the circles. 

There are other methods of indicating section parts of 
woodwork on small drawings ; the ordinary way is simply 
to put in diagonal lines of colour with the brush, reversing 
the direction of adjacent pieces. Engineers sometimes rule 
in the colour with the drawing pen, using alternately thick 
and thin lines. Architects often colour round inside the 
outline, and then put diagonal lines across. Samples of all 
these methods are shown in Fig. 202, as nearly as can be 
given in print, with black ink. 

Oak differs very much from fir and deal in the nature of 
its grain, and is much more difficult to represent. In most 
cases it will be sufficient to use a plain tint of burnt umber 
or sepia, light for elevation (Figs. 203 and 204), and 
dark for section (Figs. 205 and 206), but there are always 
some aspiring draughtsmen who want to get the best result 
from their labour, and they may be glad of a few hints. The 
difference of grain will be better understood after a short 
description of the trees themselves. Fir and deal have a 
soft, straight grain with comparatively wide and regular 
annual rings more or less strongly marked, darker on the 
outer edge of each, and with the medullary rays not showing. 
Oak has narrow, close, and irregular annual rings, with the 
medullary rays, or felt, or flower, or silver grain strongly 
marked both on the end and face. The medullary rays are 
hard plates of flattened cells more or less radial, but running 
somewhat irregularly in the length of the tree, so that when 
a board is cut to show the '' flower '^ they appear as small 
hard slabs of a lighter colour and solid texture, averaging 
perhaps l4 in. by i in. broader in the middle and slightly 
curved. 

In order to show these rays on a drawing in water-colours 
the surface must be tinted with pale burnt umber, leaving 
the light spaces, and one side of these may be softened off 
with the water brush to imitate nature more closely. The 
colour then being mixed a little darker, the rest of the 
graining may be put on, which is little more than a series 
of broken lines without softening. The same colour will be 
used for the underneath tint on the end grain ; and then, 



136 PRACTICAL DBAUGHTSMEN'S WORK. 




GOLOUEING DRAWINGS. 137 

mixing it still darker and using a fine-pointed brush, the 
end grain may be put on in thin dark lines, broken fre- 
quently, and placed rather close together. When this is 




Fio\ 205.— End Grain Oak. 



done the medullary rays may be put on with the same brush 
and colour, keeping them fairly radial, but somewhat 




'Fig, 206.— End Grain Oak. 

irregular and broken, and adding other lines as the work 
progresses towards the outer edge. The smaller pieces of 




ORDINARY. ENGINEERS. ARCHITECTS. 

Fig. 207. — Various Cross Sections for Oak. 

oak are coloured (as shown by Fig. 207) conventionally in 
the same way as described for fir and deal, the only difference 
being that burnt umber is used for oak. 



138 PF ACTIO AL DRAUGHTSMEN'S WORK 

DISTINCTIVE COLOURS GENERALLY USED IN ARCHITECTURAL 
AND MECHANICAL DRAWING. 

Banks (Steep). — Shaded with graduated warm sepia, darkest at 
top of bank , vertical hill-shading in Indian ink or dark sepia. 

Brass. — Gamboge with yellow ochre or burnt sienna. 

Bricks (Blue). — Elevation, indigo and Indian ink ; section, 
indigo. (Red).— Elevation, light red (pale) ; section, Indian red 
(dark). 

Brickwork (New). — Elevation, Roman ochre ; section, crim- 
son lake. (Old).— Elevation, Indian ink (pale) ; section, Indian 
ink (dark). 

Buildings (Brick or Stone). — Crimson lake. (Wood).— Sepia. 

Cast Iron. — Payne's grey ; neutral tint. 

Chain. — Elevation, Prussian blue (dot and stroke) ; section, no 
colour. 

Concrete. — Sepia with black marks ; or indigo, or Payne's 
grey with black marks and small light spots left. 

Copper. — Gamboge with lake ; elevation, crimson lake and 
burnt sienna ; section, crimson lake and burnt sienna (dark). 

Earth. — Burnt umber or warm sepia, left jagged at edges ; or 
sepia, light and dark. 

Electric-bell Wires. — Yellow. 

Fields and Vacant Lands. — White, 

Fir and Deal (rough).— Elevation, burnt sienna or gamboge; 
section, burnt sienna (edged round and hatched). 

Fir and Deal (wrought). — Elevation, burnt sienna (pale); 
section, burnt sienna (dark rings). 

Footpaths (Flagged). — Yellow ochre. 

Glass. — Green ; Prussian blue ; neutral tint. 

Glass Roofs. — Cross-hatching of Prussian blue. 

Granite. — Pnr])Ie madder; pale Indian ink. 

Greenheart. — Elevation, indigo and gamboge ; section, indigo 
and gamboge (dark). 

Gun-metal. — Elevation, Indian yellow ; section, Indian yellow 
(dark). 

Lead. — Indigo ; indigo with Indian ink. 

Leather. — Elevation, burnt umber (very pale) ; section, burnt 
umber (dark). 

Mahogany. — Elevation, light red and burnt sienna; section, 
liijht red and burnt sienna (dark). 



COLOURING BBAWINGS. 139 

Meadows and Cultivated Grass.— Prussian green ; Hooker's 
green. 

Oak. — Elevation, burnt umber (pale) ; section, burnt umber 
(dark). 

Pipes (Cold-water). — Prussian blue. (Gas). — Indigo with lake. 
(Hot-water). — Crimson lake. (Rain-water). — Elevation, Prussian 
blue (outline) ; section, Prussian blue (outline). (Soil). — Eleva- 
tion, burnt sienna ; section, burnt sienna (outline). 

Plaster. — Payne's grey. Plaster and Cement. — Elevation, 
Tnd'an ink (pale) ; section, Indian ink (dark). 

Pail ways. — Neutral tint between the rails of each track. 

Pope. — Elevation, burnt sienna (dot and stroke) ; section, no 
colour. 

Rosewood. — Burnt sienna with lake. 

Sewers and Drains. — Prussian blue. 

Skies (in perspectives). — Cobalt blue. 

Slate. — Elevation, Payne's grey ; section, Payne's grey (dark). 

Steel. — Elevation, violet carmine (very pale) ; section, violet 
carmine (dark) ; or indigo with a little lake. 

Stone. — Yellow ochre ; gamboge with Indian red and burnt 
umber ; sepia ; Prussian blue. Representing stone in section by 
Prussian blue is to be avoided, though in common use. Prussian 
blue should be retained entirely for wrought-iron work. 

Stone Dressings. — Elevation, French blue (very pale) section 
French blue (dark). 

Streets (Paved).— Neutral tint. 

Timber (Existing).— Elevation, Indian ink (pale); section 
Indian ink (etched). 

Tubes (Speaking).— Green. 

Water.— Elevation, Prussian blue (washed) ; section, Prussian 
blue (lines). Water may have graduated blue edges. 

Windows Inside.— Elevation, French blue (pale) ; section, 
Hooker's green. No. 2 (dark). 

Windows Outside.— Elevation, Payne's grey (dark) ; section, 
Hooker's green, No. 2 (dark). 

Wrought-iron (Bright).— Elevation, Prussian blue (very pale) ; 
section, Prussian blue (dark). (Rough).— Payne's grey. 

York and Soft Stone.— Elevation, sepia (very pale) ; section, 
sepia. 

Zinc— Elevation, French blue (very pale); section, French 
blue (dark). 



140 



CHAPTER X. 

]\rAKING A DRAWING. 

All tLe general principles upon which the drawings are con- 
structed have been dealt with, and any attentive reader who has 
worked out enlarged copies of the diagrams will have made very- 
substantial progress towards becoming a skilled draughtsman. 

In commencing a drawing the first thing is to decide where- 
abouts on the paper the various elevations, plans, and sections 
will be disposed, and of what size they can be drawn, so as to 
find sufficient room for them and their descriptions. The scale 
having been once determined, it is well to make a pencil 
memorandum of it in one corner of the margin, for it often 
happens that a drawing has to he. left uncompleted for several 
days, when the note will save the trouble of trying over various 
scales, in case the original one has been forgotten. The plans 
of a building or piece of machinery are usually placed directly 
above or below the elevations, so that the various features can 
be projected from one to the other by the use of the T square. 
End elevations are placed to the right or left of the main 
elevation, in accordance with the side which they represent. 

There is one simple and general rule which is to be observed 
in making any drawing, and that is to commence with the main 
dimensions first, and draw them in their correct positions before 
filling in the smaller details. If this be not attended to, and a 
number of small details are added one to another without first 
setting out the total length they are to occupy, it will generally 
be found that some sligbt errors in each measurement which it 
is impossible to avoid have accumulated so as to make a decided 
discrepancy. 

As an exam})le, sui)pose a front elevation of a building has 
to be set out, containing a doorway in the centre, with three 
windows on each side. When the widths and spaces are each 
set out separately, commencing at one end, and measuring each 
from the termination of the last, it will be seen that, although 
each measurement may be within one fraction of the correct 



MAKING A DR AWING. 



HI 



dimension, the total may be as much as fifteen fractions in error. 

The correct method would be 
to set off first the total length of 
the building, then to find the 
centre and set off the width of the 
doorway, and afterwards to fill in 
the windows and spaces. 

Suppose Fig. 208 to be the 
plan of the front of a small 
villa. An "over-all" measure- 
ment of 39'— 6" should first be 
put on the drawing, and then be 
subdivided as shown, into 18' — 
0" for the projecting portion and 
21'— 6" for the recessed part. 
These measurements should be 
again subdivided, showing the 
lengths of brickwork, widths of 
openings, etc. ; and a line of 
measurements inside gives the 
thicknesses of the walls, dimen- 
sions of rooms, etc. The distance 
that the part projects should 
also be noted as shown by 3' — 0". 
The inside measurements and the 
smaller dimensions should exactly 
agree with the "over-alF' measure- 
ment given. 

In drawing pencil lines they 
should always be drawn longer 
than the actual length of the 
line to be inked in, so that 
the exact point of intersec- 
tion with other lines can be 
better seen. When the drawing 
has been inked in these extra 
lengths, of course, have to be 
cleaned off with indiarubber, as 
well as a great' many other 
pencil lines which are necessary in the process": of making 
the drawing, but which form no part of the finished draw- 




142 FRAGTIGAL DRAUGHTSMEN'S WORK, 

ing. These " construction lines," as they are called, should 
be drawn as lightly as possible, so as to be easily removed with- 
out greatly damaging the surface of the paper. When drawing 
circles or arcs of circles with the compasses, a little pencil mark 
should be made round the centre-point, so that it can be found 
without any trouble when it is desired to draw it in ink. It is 
useless to draw in pencil every one of a long series of circles or 
arcs which are all alike ; it will be more expeditious to mark 
the centres only after drawing the first one or two, for in the 
inking-in of the drawing, when the compasses are once set to the 
correct radius, the centres will be all that is required to draw 
them in full. 

Every working drawing, when it leaves the draughtsman 
should be carefully and completely figured. A little time spent 
thus in figuring the builder's tracings so that the sizes of window 
openings, thicknesses of walls, etc., are clearly stated, will save 
the architect and clerk of works worry and inconvenience while 
the building is in progress. It is well for the lines along which 
the measurements are given to be drawn in colour. The ticks 
' and ^', those well-known signs for feet and inches, should be 
clearly shown, and a short dash between the feet and inches keeps 
the figures clearly apart as 6' — 10". A measurement of feet 
only should always have a cipher in the place of the inches, 
as 25' — 0". The arrow-heads, showing where the dimensions 
apply, should always be carefully and clearly marked thus : 
IK — 10-6" — >l . 

Vertical measurements showing the height of rooms are 
best figured from floor to floor, never from floor to ceiling, but 
allowance should be made for the depth of the floor. The 
height of the windows should always be figured from the top 
of the sill to the underside of the head, and their position from 
the level of the floor to the top of the sill, this giving exactly 
the opening in the brickwork. If a drawing is carefully 
figured on the lines here indicated, it is much easier for the 
workmen to carry out the work correctly, and much labour 
in superintending is saved to the architect and contractor. 

The next example for practice shows that some substantial 
progress has been made, and, while apparently working only on 
detached fragments in previous examples, a framework of know- 
ledge and skill has been built up that can now be applied to 
practical uses. 



MAKING A DB AWING. 



143 



Fig. 209 shows a small plan of an irregular piece of ground, 
bounded by straight lines and containing a cottage. This would 
be called a block plan, because the cottage is shown as a solid 
block— without details. It will be seen that every part of the 
plan is " triangulated," which means that each junction point has 
three dimensions to fix it, upon the same principle as large 
surveys are carried out. 

This block plan of a cottage and grounds is intended for 
practice in drawing to a scale of 1 in. to 8 ft. Before commenc- 
ing, ascertain the extreme length and height of the drawing, so 




Fig. 209.— Block Plan of Building and Site. 



that the base line may be drawn in a convenient position upon 
the paper. Mark off along the base the lengths shown, and, with 
the extreme left of the line as a centre, mark with the compasses 
an arc of radius on the scale equal to 24 ft. 6 in. Similarly, with 
the mark 20 ft. from the left-hand end of the base line as centre, 
strike an arc of 14 ft. radius to cut the first arc, and the inter- 
section of these arcs will fix one corner of the cottage. The right 
end of the line may be dealt with similarly, and the plan of the 
cottage completed with straight lines. Then from the left end 
of the base line strike an arc of 30 ft. radius, and from that 
corner of the cottage first found strike arcs of 31 ft. and 30 ft. 
radius, the 31 ft. radius cutting the first 30 ft. radius, and 
the intersection of these arcs will fix one of the angular 
points of the garden ground. From this angular point an arc 
of 15 ft. radius, may be struck ; this, intersecting the second 
30 ft. radius, will obtain the point A. The point B may be found 
similarly, and the plan finished by connecting A to B by a straig]it 




144 PRACTICAL DRAUGHTSMEN'S WORK 

line. Tlie length ab, measured on the scale, should indicate 
58 ft. 6 in. on an accurate drawing. 

In practically measuring any piece of ground for the purpose 
of making a plan,there are one or two principles to bear in mind 
—first, the lines upon which the measurements are taken must be 
so arranged that it is not possible to make a mistake without 
discovering it in "plotting" or "drawing to scale." For instance, 
in the present case, if the measurement 30 ft. from a had been 
taken as 29 ft., then a b would scale shorter than 58 ft. 6 in., and 
thus it would be known that there was some error ; and any other 
wrong dimension would, in the same way, distort the figure, so 
that the last line would not w^ork in correctly. Another principle 
is that where several small measurements occur in one line, as 



Scale of fee* 



Fig. 211.— Scale for Plan shown at Fig. 209. 

Fig. 210. — Measuring 
an Angle. 

piers and panels in a wall, a general dimension over all should be 
given, which should agree with the sum of the separate measure- 
ments. Thus the over-all dimension of the base line in Fig. 209 
might have been shown, as it is the sum of the running dimen- 
sions, or 20 ft. + 32 ft. + 18 ft. 6 in. = 70 ft 6 in. Sometimes, in 
order to obtain the angle one wall makes with another, a special 
measurement is taken across the angle at a little distance from 
the junction, instead of taking the whole length and the distance 
between the ends. This is shown in Fig. 210. 

The cottage may be covered, as here illustrated, with lines at 
an angle of 45^, called "hatching," to show that it is a building. 
If the scale were smaller, it might be covered over solid with a 
tint of dark Indian ink ; and if the drawing were coloured, it 
would be tinted with crimson lake, while the garden ground 
might be coloured green. 

Now make a neat scale of feet (Fig. 211) on the lower border 
line, showing 10 ft. by units and 50 ft. by tens, the units being 
numbered backwards. 

It is a good rule as far as possible to limit the writing on a 
drawing ; but, whenever writing is done, it must, first of all, be 




MAKING A DE AWING. 145 

readable, and with this object it is well to use plain block letters 
for headings, and italics for descriptive notes. Architects very 
often obscure their printing on plans by inventing new letters, 
making them of microscopical size, placing them between ink 
lines, and finally skewering them with another line through the 



ABCDEFCHI JKLMNO 
PORSTU VWXYZ&c. 

Fig. 212. — Sample Block Letters. 

Fig. 213.— Enlarged 
Drawing of the Letter G. 

centre, all upon the false idea of this being artistic. The first 
requirement of the printing upon a drawing is that it should be 
readable ; therefore, let it be neat and distinct. 

12345 6 7890 

Fig. 214. — Samples of Figures. 

The heading for the drawing shown at Fig. 209 may be 

«* BLOCK PLAN OF COTTAGE AND GARDEN GROUND." 

It is rather a long one, and the letter G occurs so often that a 
special enlarged view of this letter is given at Fig. 213, with the 
circles completed by dotted lines for comparison, to show exactly 
the shape that is recommended for this letter. 

A sample of the block letters for headings is given at Fig. 212 ; 
they may be drawn in single thin lines or thickened to a maxi- 
mum of yV^"-*) ^^^^ ^^ t^i® size of paper recommended — viz., 13 in. 
by 21 in., their height should not exceed -f^'m, for short headings, 
or i in. for long headings. Figures appearing in the heading 
(Fig. 214) should be the same size as the letters, but as dimensions 
on the drawing they should not be more than | in. deep, nor less 
than Y^m. When dimensions are put upon a drawing, the 
distance to which they extend should be carefully shown by 
dotted lines, with arrow heads at the extremities, keeping the 
fractions level, as shown (Fig. 79, p. 50), and with the small figures 
two- thirds the size of the large ones. The feet should be marked by 
a single accent thus, ', and the inches by a double accent thus, " 
J 



146 PRACTICAL DRAUGHTSMEN'S WORK 

with a full stop on the line between the figures. If the dimen- 
sions consist of an even number of feet, then inches should be 
represented by . O". The omission has led to serious mistakes in 
practical work, which should always be guarded against, and, not- 
withstanding the examples of text-books and the practice of some 
examiners, this is an important point always observed by practical 
draughtsmen. 

After inking in all the figures, pencil out the heading very 
carefully, making the letters a little thicker than those used in 
Fig. 212 ; G, R, S, C, and M will be found the most difficult. The 
distance apart of the letters should not be quite uniform, but 
should be such as will look uniform. For example : an I between 
M and N would require more than the usual space to look right ; 
on the other hand, a T between L and J would require to slightly 
overlap to give the right effect. The junction points of A, M, N, 
V, and W should not be sharp, but the same width as the thick- 
ness of the strokes. 

Leave J in. between the words of the heading, it is then much 
easier to read than if cramped closer together or spaced wider 
apart. Eemember that the printing— being thicker — will take 
longer to dry, and be careful not to use the indiarubber too soon. 
It will be observed that the guide lines for the square, and centre 
lines for the circle, as described above, have not been inked in, as 
they would spoil the effect of the drawing, but on machine draw- 
ings it is usual to put the centre lines in red, using a little 
crimson lake for the purpose. 

The example on p. 147 shows the usual arrangement of a 
set of drawings for a house, but in this case the house is of the 
smallest possible dimensions, and contains one room only. It is 
about as simple an illustration as can be imagined, but it will 
form a stepping-stone towards the making of elaborate drawings. 
A scale of one-eighth of an inch to one foot is the usual scale for 
complete buildings, upon sheets of imperial paper, 30 in. by 22 in. 
with details to various larger scales according to the subject, as 
1 in., l^in., 3 in., and 6 in. to 1 ft., and full size for mouldings. 

In drawing the present example, begin with the plan (Fig. 215), 
as is usual in all ordinary cases, and from that })roject the front 
elevation (Fig. 216), then the side elevation (Fig. 217), back 
elevation (Fig. 218), and sections (Figs. 219 and 220). When 
finished and inked in, the drawing may be coloured, carefully fol- 
lowing the directions given in the chapter dealing with that subject 



MAKING A DRAWING. 








CO 

i 




Figs. 215 to 220.— Usual Arrangement of a set of Drawings of a House 



143 



FBAGTICAL DRAUGHTSMEN'S WORK 



A draughtsman, before he begins to make his own designs 
or to draw from actual solid objects, generally makes copies 
of existing drawings. When these consist of straight rect- 
angular outlines, no particular difficulty is experienced, bub 
when the outline is irregular a beginner may be rather at a 
loss to know how to proceed. For instance, the outline (Fig. 
221) would be copied as shown in Fig. 222. First a horizontal 
line is drawn from point A, then an arc a 5 of any convenient 
radius is drawn from point A to cut the horizontal line xi B. 
Select a starting point on the paper corresponding to point A, 
draw an arc with the same radius A a, and take the length of 





Fig. 221.— Irregular Outline to 
be Copied. 



Fig. 222.— ]\Iethod of Copying 
an Irregular Outline. 



chord a & in the compasses, and from a on the new drawing cut 
the arc at b, and draw A h prolonged, cutting it off at B to the 
required length. If it were desired to copy the drawing to 
twice the scale, the lengths of all the lines would have to be 
doubled, but the angles would be unaltered ; similar figures 
differ in their sides, but not in their angles. Then to copy 
the angle at b, take any radius b c and strike the arc c d ; upon 
the new drawing do the same, cutting off the arc to the chord 
length c d and drawing b c the right length through d ; the 
next angle at c is set off in exactly the same way. The curve 
D E following requires different treatment, so it will be lef b 
for the present and work resumed round the other way. Line 
A F will be obtained as the previous ones have been, and then 
a base line is drawn from f to e, leaving all the irregular out- 



MAKING A LRAWING, 149 

line on one side of it. The angle and length of this base line 
will be copied as before, while for the outline the method of 
distances and offsets will be used. Notice the salient points 
of the curvature, that is, the most projecting points whether 
outwards or inwards, as e g n ; put in short lines at right 
angles to the base line to meet these points, then copy their 
lengths and distances from F E, obtaining points e f g h. 
Through these points lightly sketch a continuous curve, after- 
wards using a French curve and hard pencil for greater neat- 
ness. A similar base line, or chord line, may be drawn across 
the remaining portion D E its length, and the angles fed are 
copied as before. This should bring point d exactly where 
c D terminated ; if it does not, it will be well to check the 
work all through again. Assuming the outline from d to B 
to be a compass curve, the centre may be found by first bi- 
secting the chord of the whole arc and then the chord of half 
the arc, the intersection being the exact spot to put the point 
of the compasses to draw the curve. 

If a mere copy of Fig. 221 were desired, much shorter 
methods might be adopted ; the simplest would be a tracing 
on tracing paper. To obtain a tracing from any drawing, 
place it on the board with the main lines horizontal and 
vertical ; lay the tracing paper upon it ; then cut four pieces 
of blotting paper, each 2 in. square, fold them twice so as to 
make pads 1 in. square, and place a drawing pin through one 
pad at each corner of the tracing paper to hold it firm and 
prevent it from tearing. Then go over all the lines of the 
original with drawing pen or pencil, and the tracing will be 
complete. If tracing linen is used instead of tracing paper, 
pads need not be used under the drawing pins. 

Another mode of copying is to place the drawing over a 
clean sheet of paper and prick through all the junctions of the 
lines, and, on curves, some intermediate points also. Then 
remove the drawing and join up all the pricked points to 
match the original. Another method is to lay a sheet of 
carbon paper, or a piece of blackleaded tracing paper, on the 
blank sheet, place the drawing over it, and then with a blunt 
point, like a scriber rounded over at the end, trace firmly 
over the outline of the drawing, which will transfer all the 
lines on to the blank sheet. 

Where the drawing is complicated, or several copies are 
required, the photographic method is the best way of copying, 



150 



PRACTICAL DRAUGHTSMEN'S WORK. 



giving either white lines on a blue ground, blue lines on a 
white ground, or black lines on a white ground ; the last- 
named result is the most expensive, but very much to be pre- 
ferred. In order to be able to produce a good photograph, 
the drawing must be in very black ink on bluish tracing 
paper, but a drawing on thin white drawing paper can be 
copied fairly well. 

An instrument which is useful in certain cases for copying 
drawings is the three-legged compasses. It is like a pair of 
dividers with an extra leg pivoted at a right angle to the 
other two, and two of the legs being set upon points as A a 




Fig. 223.- 



-Small -squared Plan 
of Estate. 



Fig. 224. — Method of Enlarging by 
Squares. 



(Fig. 222) ; the third is set on B, and the setting is pricked off 
on the new drawing. Then two being set to A B the third is 
put on c and transferred. Then two being set upon A c the 
third is pub on d, and so on ; or from any given base line any 
number of points, however placed, may be truly copied. 

When a drawing has to be copied to a different scale from 
the original, there are instruments such as the proportional 
compasses, the pantagraph, and the eidograph. These, how- 
ever, are expensive, and must be used with great care to 
produce a good result. The use of the proportional com- 
passes involves almost as much labour as constructing the 



MAKING A DRAWING. 151 

drawing from the commencement, but they are occasionally 
useful for straight-lined drawings. For estate plans the other 
two instruments are more appropriate, but practically they 
can be used for making reduced copies only with any degree 
of accuracy. 

The mosit draughtsmanlike method to employ for enlarg- 
ing is that of copying by means of similar squares. Suppose, 
for instance, a plan drawn to a scale of 60 ft. to one inch has 
to be enlarged to a scale of 40 ft. to one inch, as shown in the 
accompanying illustrations (Figs. 223 and 224). Find the 
largest convenient number that divides without remainder 
into the two scales— in this case 20, where 40 -=- 20 = 2, and 
60 -^ 20 = 3, so that 2 and 3 are the numbers required. Then 
draw lines horizontally and vertically over the original draw- 
ing (Fig. 223) i in. apart — that is, three spaces to the inch, 
making every third line thicker than the others. For the 
enlargement (Fig. 224) the lines mus-t be i in. apart, or two 
spaces to the inch, and every third line must be thickened as 
before. As a record of the method, it will be advisable to 
rule in the squares with Prussian blue or crimson lake, but 
as their use is only temporary it is not customary for them to 
appear upon office drawings. Now begin at any part of the 
drawing, but preferably at the top left-hand corner, as at A 
on Fig. 223) ; notice at what proportion of the square the line 
starts, and then at the corresponding point on the blank form 
start a line. Notice the direction of the line, where it cuts 
the next side of the square, and what shape the intermediate 
portion is. Then follow the line along in the same way 
through each corresponding square until b is reached. Next 
go on from c to d in the same way, and so on until all the lines 
on the original appear upon the enlargement. After dealing 
in this way with each line, a general view should be taken of 
the whole, and any noticeable errors corrected, the sides of 
the buildings being ruled in to straighten them from the 
, sketching. 

If a finished drawing is required, the outlines may now be 
inked in, all the pencilling rubbed out, the different parts 
coloured or ruled in black and white, and the title put on. 
Sometimes, to avoid damage to the original, the squares are 
made upon tracing paper laid over it, and if the copy is only 
required to be upon tracing paper this might have under- 
neath it a second sheet of tracing paper with suitable squares. 



152 PRACTICAL DRAUGHTSMEN'S WORK 

The illustrations on pp. 152 and 153 show conventional 
signs in use for most of the objects usually indicated on 
maps. Such conventional signs are in general use for com- 
mon objects of all kinds. 

Tracing forms an important branch of draughtsmen's 



^'■T:: Jtt ^-^^■^ ■-■■■■'■ — ^''"z..^. ^ -^^-^ 



— , /f\/K /T\ /l^ '^ X A 

l^gjT ~^"y" AAA i III 

ft\«Lo»NGSK GARDENS -. Toc^^i^Curfs- - Hop Gkounds- 



r 



K^ :) 



^ 




__.j /2. 




^Jjli." . •"Ui.iiiMHlBH"""' ^»^' ~ 

I :rrTn^'—' ^nmr >' ' ^ - ■ '' ■' ' ''' » 

T^ML^As^ DoufiLE Line.- -'^A.iLW^y 'b\NGLEL UNE.- 

Close p-^UNGS — Y(\rAOW\>LV. A - f 

Tost Houi^e. - ~~^ '^}~^ 5pi?m& .« >Ne.uu • (D 

CnuircH ^Crt*.PiLu- (ZJ^ ^Mi-yHy ... ^ 

Fig. 225. — Conventional Signs u^ed by Diaughtsinon. 

work. Tracings are made on either paper, cloth, or linen, 
paper being used where strength is not important. Tracing 
paper and tracing cloth is sold in sheets and rolls of vary- 
ing sizes and lengths. As a rule, the rolls are the more 
economical to buy. When tracings are required for repro- 



MAKING A DRAWING. 



153 



duction by any of the blue print processes, paper or cloth of 
a blue tinge should be selected, as the lines come out clearer 
than when a yellow tinted material is used. As tracing 
cloth generally stretches after being cut off the roll, it should 
be mounted a day before it is required, and stretched again 



4 f A r ju' ^ x -^ • . 



/' 



/ 



/: 



4 4. 






P\NE. YIOOOS- C,RCHARD5l\Tl^EES- flELOS vnvtw*.v^>T'^oot y^.^ES 




LAHD auajetT' to 
- \HUNOATiOH. 



• c5AND HiuV/b- 






• COMftA<,«, W.ATiO.4- 



C.-K*»^T 


/ 


-j:::^:;^:^ 






w-^N^-. 


TELEGKA.PH L\Me. 


WAfti^muu - - 


=r.-<fr' 


W^u\.^ . 






bN\e K\lns - -- 


® 1 



• FTsOT ^*<^^m 



'^AiL^NG'a -o Hurdle «3 



Fig. 226.— Conventional Signs used by Draughtsmen. 



to remove the creases. In mounting the tracing paper or 
cloth over the drawing, pin down the centres first, and work 
up to the corners. 

Tracings in pencil are often made for use in the work- 
shops ; when required only temporarily and not to be kept 



154 PRAGTIOAL DRAUGHTSMEN'S WORK. 

as a record, or where they will not be subjected to much 
handling, such tracings are quite sufficient for the purpose. 
The sections should be tinted on the back of the tracing. It 
is a good plan to use the pencil and tracing paper when 
working out a design or a scheme ; for instance, the plan of a 
first floor and successive storeys may be designed on tracing 
paper over the ground floor plan, and the movements of 
working parts of machinery can be seen by making paper 
tracings of the several parts, and moving them to the posi- 
tions they would occupy in actual work. Tracing paper is 
also useful when designing ornamental work where any part 
is repeated. A tracing is made with an H.B. pencil, the 
tracing turned over and placed on the drawing where the 
repetition is required, and the lines gone over with a fine 
pencil or tracing point, which will give a faint impression 
of the drawing reversed on the paper beneath. 

Indian — or, more properly, Chinese — ink is the best for 
tracing as well as for drawing. The hexagonal sticks, cost- 
ing about 5s. each, are the best. A few drops of water should 
be put into a 4-in. saucer, and the ink rubbed up on this 
with a circular motion, the object being to grind the particles 
thoroughly. lb will take from ten to twenty minutes to 
prepare a saucer of ink. A little experience will enable the 
operator to determine the required thickness, the consist- 
ency of the liquid being judged from time to time by blowing 
on the surface. When too thin the ink will make a grey line, 
and if too thick will not flow freely from the pen. For draw- 
ing on paper of which the surface has to be washed over with 
colour, a little bichromate of potash should be rubbed up 
with the ink, a piece the size of a pin's head being used for 
a saucer ; but care must be taken with this material, for if 
much is put in a yellow smear will stain the paper on each 
side of the lines. If the tracing cloth or paper has a greasy 
surface, a small quantity of prepared ox-gall or soap is rubbed 
up with the ink ; but it is better, when possible, to avoid 
using these, and to dust over the surface of the tracing with 
whiting, all of which must be rubbed off with a clean duster. 
The saucer containing the ink should be kept covered with 
another saucer, whicli .should be removed only for dipping 
in the pen. Liquid inks to be bought ready for use are very 
convenient. 



MAKING A DRAWING. 155 

Drawings during progress should be protected from dust as 
much as possible, for in spite of all care that can be taken, it 
will be certain to be more or less soiled by the rubbing of the T 
square and set-squares. These should always be dusted before 
use, and w^hen the drawing is not being worked on it should be 
covered over with a sheet of paper. Brown paper is commonly 
used for this purpose, and in most cases is suitable enough ; but 
for very fine work it is said to be objectionable, on account of 
its tarry nature. Newspaper is apt to leave the marks of 
printers' ink. If the drawing is one which is likely to occupy a 
long time before completion, a sheet of paper should be gummed 
or pinned to the board, covering the w^hole of the paper, and 
arranged so as to expose bnly the portion of the paper which is 
required for immediate use. This can be done either by folding 
back the paper or by cutting out small squares, and patching 
them up again when that portion is drawn. After the drawing is 
quite completed, it should be cut off the board with a sharp 
penknife and a steel straight-edge. A shoemaker's knife is a 
useful tool for this purpose, as well as for cutting cardboard and 
other work of a similar nature in the drawdng- office. 



INDEX. 



Anpfles, Ronnd, 60-63 
Angular riojecdion, 97-100 

, Brick Drawn in, 97 

, Grating Drawn in, 98 

, House Drawn in, 9S-]00 

Annulets, 65 

Antiquaiian Size Paper, 14 

Arc, Camber, SI -83 

, Drawing, 55 

, Finding Centre of, 55, 56 

, Flat, 81-83 

, Circular, 67 

, Elliptical, 68 

, Equilateral, 68 

, Flat-pointed, 08 

■ , Jack, 67 

, Lancet, 08 

, Ogee, 08 

■ , Segment, 67 

Arch, Semi-circular, OG, 79 

, Semi-elliptic, 81 

, Skew, 79-81 

, Straight, 83 

, Tudor, 67 

Arrow-heads on Drawings, 142 
Asymptote, 86 
Atias Size Pajter, 14 
Back Lining, 104-113 

Drawing of Chequered Cover- 
plate, 111 

Cube, 104-106 

Cylinder, 100-108 

Grating, 109, 110 

Banks, Colouring, on Drawings, 138 
Bath Stone, Colouring, on Drawings, 128 
Battens on Drawing board, 11 
Beam Compasses, 32, 81 

, Home-made, 32-34 

Bell Wires, Electric, Colouring, 138 
Bisecting Compasses, 31 
Block Lettering, 145, 146 

Plan, 143, 144 

Border Lines, 39 
]iow Compasses, 31 
Bows, Curve, 34 

, Pump, 32 

, Spring, 31, 32 

Boxwood Scales, 117 

Brass, Colouring, on Drawings, 138 

Brick Buildings, Colouring, 13S 

Drawn in Angular Projection, 97 

liricks. Blue, Colouring, 138 

lied, Colouring, 138 



Brickwork, New, Colonririg, 133 

, Old, Colouring, 138 

Broken or Dotted Lines, 49 
Brushes, Colour, 127 

, Filling, with Colour, 131 

Builders' Working Drawin<jcs, 96 

, Scales for, 115, 120 

Building, Brick, Colouring, 138 

, Front Elevation of, 140, 141 

, Plan of, 141 

, Representing, Conventionally, 152 

, Stone, Colouring, 138 

, Wood, Colouring, 138 

Camber Arc, 81-83 

Canal, Representing, on Map, 153 

, Lock on, 153 

Cardboard Scales, 117 

Cart Track, Representing, on Map, 153 

Cartridge Paper, 13 

Cases of Instruments, 22, 23 

Castings, Drawing Edges of, 57-60 

Cast-iron, Colouring, on Di-awing, 138 

Column, 91 

Grating in Angular Projection, 97 

, Back Lining, 100,' 1 10 

, Drawing Plan of, 108, 109 

Cavetto Moulding, 64 

Cement, Colouring, on Drawing, 129 

and Plaster, Colouring, 139 

Chain, Colouring, on Drawings, 138 

Chapel, Representing, 152 

Chequered Cover-plate, Back Lining, 111 

, Drawing, 110, 111 

Chinese Ink, Rubbing up, 154 
Church, Representing, on Map, 152 
Circles, Finding Centres of, 53 

for Practice, 56, 57 

, Projecting Ellipses from, 72, 73 

, Two, Constructing Ellii>se from, 74 

Circular Arch, 67 

Lines, Drawing, 52-69 

Clear^ Drawings, 155 
Cleaning Ruling Pen, 25, 26 
Cliffs, Hei)resenting, on Map, 152 
Cloth, Tracing, 15, 152 

, , Mounting, 153 

, , Preparing Ink for, 154 

Cloth-mounted Pa])er, 14 

Cohl-water Pipes, Colouring, 139 

Columbia Size Paper, 14 

Colour, Ai)plyiiig, to Drawings, 131 

Colour Brushes, 127 

, Filling Brush witli. 131 



INDEX. 



157 



Colour, Rubbing up, 131 

Saucers, 127 

Slants, 127 

Coloured Drawings, Ink for use with, 154 
Colouring Drawings, 126-137 

, Leaving Margin when, 132 

Colours, Combining, 129-131 

— , Primarj^, 129-131 

Column, Fluted, Drawing, 111, 112 

Columns, Tall, 89-91 

Compass Variation, K,eprcsenting, 153 

Compasses, 28-34 

, Beam, 32, 81 

J , Home-made, 32-34 

, Bisecting, 31 

, Bow, 31 

, Curves made with, 52-69 

' , Electrum, 29 

, Hair Dividers, 33 

, Holding, 53, 69 

, Leg Joints of, 29 

, Needle-pointed, 28, 29 

, Plain-pointed, 23 

, Proportional, 30, 31, 150, 151 

, Spring Bow, 31, 32 

, Testing, 29 

, Three-legged, 150 

, Trammel, 32-34, 81 

Concrete, Colouring, in Drawings, 138 
C(me, Sliading, 71 
Conic Sections, 70, 71 
Construction Lines, 141, 142 
Copper, Colouring, in Drawings, 138 
Copying Drawings, 148-15] 

with Eidograph, 150, 151 

Pantagraph, 150, 151 

by Photography, 150 

Pricking, 149 

Squares, 151 

with Three-legged Compasses, 

150 

by Tracing, 149 

Cover-plate, Chequered, Back Lining, 111 

, , Drawing, 110, 111 

Cube, Back Lining, 104, 105 

, Hollow, Back Lining, 103, 106 

Cuive Bows, 34 
Curved Angles, 60, 63 
Curves, Compass, 52-09 

, Elliptical, 70-91 

; Flat, 53, 54, 81-83 

, French, 35 

, , Using, 35, 36 

, Hyperbolic Expansion, 86 

in Machine Construction, 59 

, Parabolic, 83-87 

, Rai.lway, 35 

Cyma Recta Moulding, 64 

Cyma Revcrsa Moulding, 64 

Cylinder, Back Lining-, 106-108 

Datum, Ordnance, 125 

Deal, Colouring, in Drawings, 132, 138 

, Grain of, 135, 

Demy Size Paper, 14 

Desk for Drawing Office, 13 

Diagonal Scale, 121 

Dimension Lines, 49 

Dimensions on Drawings, 144, 146 



Dividers, Hair. 30 

Dotted Lines, 39 

Dotting Pens, 27, 28 

Doubl.3 Elephant Size Paper, 14 

Emperor Size Paper, 14 

Ruling Pen, 24 

Drains, Colouring, in Drawings, 139 

Draughtsman at Work, Position of, 11, 12 

Drawing-board, 10 

, Battened, 10, 11 

, Cutting Pap 'r from, 155 

, Inclining, 12 

, Ink-stained, 18 

, Preventing, from Warping, 11 

, Renovating, 11 

, Securing Paper to, 15 

, Straining Paper on, 16-18 

, Testing, 42 

Drawing-office, Desk for, 12, 13 

, Lighting of, 12 

Drawing-paper (see Paper) 

Drawing-pins, 16 

Drawings, Back Lining, 104-113 

, Builders' Working, 96 

, , , Scales for, 115, 120 

, Colouring, 126-137, 

, Commencing, 37, 140 

, Covering, whilst working on, 155 

, Figurine:, 142 

, Hatching, 144 

, Keeping Clean, 155 

, Lettering on, 145, 146 

, Machine Construction Working, 96 

, Making, 140-155 

, Mechanical, Scales for, 115-120 

, Plotting Scales on, 119 

, Position of Scale on, 119 

, Removing, from Board, 155 

, Test, 43-48 

Dust, Keeping, from Drawings, 155 

Earth, Colouring, in Drawings, 138 

Eidograph, Copying Drawings with, 150, 
151 

Electric Bell Wires, Colouring, in Draw- 
ings, 138 

Electrum Instruments, 29 

Elephant Size Paper, 14 

Elevational Projections, 102, 103 

Ellipse Cfmstruction from TwoCirrles, 74 

, Drawing, with Compasses, 75 

, , — — Paper Trammel, 76, 77 

, , String, 73, 74 

, Gardeners Method of Setting out, 78 

, Joiner's Method of Drawing, 77, 78 

, Patternmaker's Method of Drawing, 

77, 78 

, Projecting, from Circle, 72, 73 

Ellipses, 70-78 

Elliptical Arch, 68 

Curves, 70-91 

Emperor Size Paper, 14 

Entasis, 89-91 

, Tredgold's, 90, 91 

Equilateral Aich, 68 

Erasing, 39 

Expansion Curve, llyp( rbolic, 86 

Feet and Inches, Symbols for, 145 

Fields, Colouring, in Drawings, 138 



158 



PBAGTIGAL DRAUGHTSMEN'S WOEK. 



Fields, Representing, on Maps, 153 

Figuring Drawings, 142 

Fillets, 65 

Fir, Colouring, in Drawings, 132, 138 

, Grain of, 135 

Cross-sections, Colouring, 135 

Flagged Footpaths, Colouring, 138 
Flat Arc, 81-83 

Curves, 53, 54 

Flat-pointed Arch, 68 

Fluted Column, Drawing, 112, 113 

Pilaster, Di awing. 111, 112 

Foolscap Size Paper, 14 

Footjiatlis, Colouring, in Drawings, 138 

, Representing, on Maps, 153 

Foi-ty-eighth Scale, 117 
French Curves, 38 

, Using, 35, 36 

Gantry Drawn in Projection, 103 
Gardener's Ellipse, 78 
Gas Pipes, Colouring, in Drawings, 139 
Glass, Colouring, in Drawings, 138 

Roofs, Colouring, in Drawings, 138 

Works, Representing, on Maps, 153 

Gorse, Representing, on Maps, 152 
Graining, Colouring, in Drawings, 132-137 
Grand Eagle Size Paper, 14 
Granite, Colouring, in Drawings, 129, 138 
Grass-grown Land, Colouring, in Draw- 
ings, 139 
Grating in Angular Projection, 97 

■ , Back Lining Dravving of, 109, 119 

• , Drawing Plan of, 108, 109 

Grecian Mouldin<:s, 64 

Greenheart, Colouring, in Drawings, 138 

Gun-metal, Colouring, in Drawings, 138 

Hair Dividers, 30 

Hand -made Paper, 13 

Hatching Drawings, 144 

Headings for Drawings, 145, 146 

Heart in Wood, Colouring, 134 

Heath, Re})resenting, on Maps, 152 

Helix, 88, 89 

Hexagonal Nuts, Curves on, 86 

Hills, Sand, Rein-esenting, 153 

Hollow Cube, Rack Lining, 105, 106 

• Cylinder, Back Lining, 100-108 

Moulding, 64 

Hop Grounds, Representing. 152 
Hot-water Pipes, Colouring, in Drawings, 

139 
House in Angular Projection, 98-100 

Plan to Scale, 120, 121 

• Post, Representing, 152 

, Set of Drawings of, 146 

Huidh'S, Representing, 153 
Hyperbola, 71 

to fill Rectangle, 87 

Hypt'rl)olic Expansion Curve, 86 
Im})crial Size. J'aper, 14 
Inches, Symbol for, 145 
Inclination of Drawing-board, 12 
Ink, C hinese or Indian, 154 

for Coloured Drawings, 154 

, Filling Ruling Pen with, 50 

, Pieparing Tracing-paper for, 154 

, Rubbing up, 154 

Inking-in Straight Lines, 49-51 



Instrument Cases, 22, 23 

Rolls, 22 

Instruments, 9-36 

Iron, Colouring, in Drawings, 132, 138, 

139 

Works, Representing, 153 

Isometrical Projection, 92, 100, 101 

, Brick Wall Drawn in, 102 

, Cube Di'awn in, 101 

, False, 96, 97 

Jack Arch, 67 

Joiner's Ellipse, 77, 78 

Joynson's Paper, Sizes of, 14 

Kilns, Representing, 153 

T>ancet Arch, 68 

Land, Inundated, Representins;, 153 

, IMarshy, Representing, 152 

, Meadow, Colouring, 138 

, Measuring, 144 

Plan to Scale, 121 

, Vacant, Colouring, 138 

, Wooded, Representing, 152, 153 

Lead, Colouring, in Drawings, 13S 
Leather, Colouring in Drawings, 138 
Lettering on Drawings, 145, 146 
Lime Kilns, Representing, 153 
Linen-mounted Paper, 14 
Lines, Border, 39 

, Broken, 49 

, Circular, Drawing, 52-69 

, Construction, 141, 142 

, Dimension, 49 

, Dotted, 39 

in Error, 39 

, Pencil, 141, 142 

, Projections of, 92-96 

, Shadow (see Back Lining) 

, Straight, Drawing, 37-51 

Lock on Canal, Representing, 153 
Machine Construction Curves, 59 

Working Drawings, 96 

^lachine-made Scales, 121 

Mahogany, Colouring, in Drawings, 132, 

138 
Manhole Cover-plate, 110, 111 
Maps, Conventional Signs on, 152, 153 

, Ordnance, 123-125 

, Scale of, 121, 123 

Marshy Land, Representing, 152 

Meadows, Colouring, in Drawings, 139 

Measurements on Drawings, 142, 144 

Measuring Land, 144 

Mechanical Drawings, Scales for, 115, 120 

Medium Size Paper, 14 

Medullary Rays, Colouring, in Drawings 

1:^.5, 137 
Mouldings, 63-66 

Needle Points of Compasses, 28, 29 
Nibs, Pen, 24-27 
Ninety-sixth Scale, 119 
Nuts, Hexagonal, Curves on, 86 
Oak, Colouring, in Drawings, 132, 139 

Cross-sections, Colouring, 135 

Ogee, 63, 64 

Arch, 68 

Oiling Ruling Pen, 24 
One-hundred-and-twentieth Scale, 117 
Orchards, Representing, in Maps, 153 



INDEX. 



159 



Ordnance Datum, 125 

Maps, 123-125 

Scale, 119 

Orthographic Projection, 92, 100, 101 

Ovals, 70 (see also Ellipse) 

Ovolo Moulding, 64 

Palings, Representing, in Maps, 152 

Pantagraph, 150, 151 

Paper, 13-15 

, Cartridge, 13 

, Cloth-mounted, 14 

, Cutting, from Drawing Board, 155 

, Hand-made, 13 

, Joynson's, 14 

, Linen-mounted, 14 

, Rolls of, 14, 15 

, Securing, to Board, 15 

, Sizes of, 14 

, Squared, 15 

, Straining, on Board, 16-18 

, Surfaces of, 13, 14 

, Tracing, 15, 152 

, , Mounting, 153 

, , Preparing Ink for, 154 

Trammel, Drawing Ellipse with, 74 

, Wetting, 18 

, Whatman's, 14 

Parabolas, 71, 83-87 

Parallel and Perpendicular Lines, Draw- 
ing, with Set-squares, 20, 22, 42 

Paths, Colouring, in Drawings, 138 

• , Foot, Representing, 153 

Patternmaker's Ellipse, 77, 78 

Paved Streets, Colouring, in Diawings, 
139 

Pencil Lines on Drawings, 39, 141 

Tracings, 153, 154 

Pencils, 38 

, Sharpening, 38 

for Tracing, 154 

Pens, Dotting, 27, 28 

, Ruling, 24-27 

, , Cleaning, 25, 26 

, , Double,' 24 

, , Filling, with Ink, 50 

, , with Ink Reservoir, 24 

, , Lift-up Nibs, 24 

, , Oiling, 24 

, , for Pocket, 24 

, , Setting, 26, 27 

, , Sharpening, 26 

, — — , Swivel, 25 

Perpendiculars and Parallels, Drawing, 
with Set-squares, 20, 22, 42 

Photography, Copying Drawings by, 150 

Pilaster, Fluted, Drawing, 111, 112 

Pine, Colouring, in Drawings, 132 
. Woods, Rei)resenting, 153 

Pins, Drawing, ]6 

Pipes, Cold-water, Colouring, 139 

■ , Gas, Colouring, 139 

, Hot-water, Colouring, 139 

, Rain-water, Colouring, 139 

, Soil, Colouring, 139 

Pitch Pine, Colouring, in Drawings, 132 
Plan, Block, 143, 144 

of House to Scale, 120, 121 

Land to Scale, 121 



Plan, Scale of, 121, 123 

Plaster, Colouilng, in Drawings, 139 

with Cement, Colouring, 139 

Plotting Scales, 119 
Pocket Ruling Pen, 24 
Portland Stone, Colouring, 128 
Post House, Representing, 152 
Pricking Drawings, 149 
Primary Colours, 129-131 
Printing on Drawings, 145, 146 
Projection, 92-103 

, Angular (see Angular) 

in Elevation, 102, 103 

, Gantry Drawn in, 103 

, Isometrical (see Isometrical) 

of Line, 92-96 

, Pseudo-isometrical, 96, 97 

, Window Opening in, 102, 103 

Proportional Compasses, 30, 31, 150, 151 
Pseudo-isometrical Projection, 96, 97 
Pump Bows, 32 
Quarter Scale, 116, 117 
Quarter-round Moulding, 64 
Railings, Representing, in Maps, 153 
Railway Curves, 35 
Railways, Colouring, in Drawings, 139 

, Representiijg, in Maps, 152 

Rain-water Pipes, Colouring, in Draw- 
ings, 139 
Rectangle, Hyperbola to fill, 87 
Red Sandstone, Colouring, 129 
Reversa Ogee Moulding, 64 
Roads, Represeiiting, in Maps, 152 
Rocks, Representing, in Maps, 152 
Roll of Instruments, 22 
Roman Mouldings, 64 
Roofs, Glass, Colouring, 138 
Rope, Colouring, in Drawings, 139 
Rosewood, Colouring, in Drawings, 139 
Round Axles, 60-63 
Royal Size Paper, 14 
Rulinf^ Pens (see Pens) 
Sand Hills, Representing, in Maps, 153 
Sandstone, Colouring, in Drawings, 121, 120 
Saucers for Colour, 127 
Scale, 114, 115 

, Boxwood, 117 

for Builders' Drawings, 115, 120 

, Cardboard, 117 

, Diagonal, 121 

Drawing of House Plan, 120, 121 

Land Plan, 121 

on Drawing, Position of, 119 

Drawings, 114-125 

, Forty-eighth, 117 

, Machine-made, 121 

for Mechanical Di-awings, 115, 120 

, Ninety-sixth, 119 

, On(vhundred-and-twentieth, 117 

, Ordnance, 119 

, Quarter, 116, 117 

, Twelfth, 117 

, Two-thousand-five-hundrcdth. 119 

Scay)e Moulding, 65 
Scotia, 65 
Screw Threads, 88 
Secondary Tints, 129 131 
Sections, 50 



IGO 



PR AG TIC AL DRAUGHTSMEN'S WORK 



Sections, Colouring, 132-137 

of Cone, 70, 71 

Segment Arcli, 67 
Semi-circular Arch, 60, 79 
Senu-elliptic Arcli, SI 
Set-square^:, 90-22 

, Angles of, 21 

, Drawing Perpendiculars and Taral- 

lelswjtli, 20. 22, 42 

, Ebonite. 21 

, Framed, 21 

, Testing, 41 

, Vulcanite, 21 

Setting Ruling Pen, 26, 27 

Sewers, Colouring, in Drawings, 139 

Shading Cone, 71 

Shadow Lines (see Back Lining) 

Sharpening Pencils, 38 

Ruling Pens, 20 

Skew Arch, 79-81 

Skies, Colouring, in Drawings, 139 

Slants for Colour, 127 

Slate, Colouring, in Drawings, 139 

Smithy, Representing, 152 

Soil Pipes, Colouring, in Drawings, 139 

Speaking Tubes, Colouring, 139 

Spiral Staircases, 88 

Splines, 34, 35 

Spring Bow Compasses, 31, 32 

Spiings of Water, Representing, 152 

Squared Paper, 15 

Squares, Copying by means of. 151 

Staircases, Spiral, 88 

Steel, Colouring, in Drawings, 139 

Stone, Bath, Colouring, 128 

Buildings, Colouring, 138 

Column, 91 

Dressings, 139 

, Portland, Colouring, 128 

, Red Sand, Colouring, 129 

, Sand, Colouring, 121 

, Soft, Colouring, 139 

, Usual Colour for, 139 

, York, Colouring, 128, 139 

Straight Arch, 83 

Lines, Drawing, 37-51 

Stiaiglit-ed„e, Testing, 39, 40 
Streets, Paved, Colouring, 139 
String, Drawing Ellipse with, 73, 74 
Snjier Royal Size Paper, 14 
Swivel Ruling Pen, 25 
Tab'c for Drawing Office, 12, 13 
Telciiraph Line, Representing, in Mai)S, 
153 

, Office, Rejtrescnting, 153 

Templates, Use of, 36 



Test Drawings, 43-48 
Testing Compasses, 29 

Drawing- board, 42 

Set-squares, 41 

Straight-edge, 39-40 

T-square, 39-41 

Threads, Screw, 88 

Three-legged Compasses, 150 

Timber, Colouring, in Drawings, 126-139 

Tints, Secondary; 129-131 

Tracing, Method of, 149, 153 

in Pencil, 153, 154 

, Pencils for, 154 

Tracing-cloth, 15, 152 

, ]\louiiting, 153 

, Preparing, for Ink, 154 

Tracing-] aper, 15, 152 

, IVFounting, 153 

, Preparing, for Ink, 154 

Trammel Compasses, 32-34, 81 

, Paper, Drawing Ellipse with, 74 

Tredgold's Entasis, 90, 91 

Trees, Representing, in Maps, 153 

T-squares, 19, 20 

, Testing, 39-41 

, Wood for, 19 

Tubes (see also Piprs) 

, Speaking, Colouring, 139 

Tudor Ai'ch, 67 

Turned Ovolo Moulding, 65 

Twellth Scale, 117 

Two-thousand-five-hundredth Scale, 119 

Valve-pit Cover-plate, 110, 111 

Villa Plan, 141 

Walls, Representing, in Maps, 153 

Warping, Preventing Drawing-board from, 

11,12 
Water, Colouring, in Drawings, 139 

Mill, Representing, in Map, 153 

Spring, Representing, in Map, 152 

Well, Representing, in Maps, 152 
Whatman's Paper, Sizes of, 14 
Windmill, Representing, in Mops, 152 
Window Opening Drawn in Projection, 103 
Windows, Colouring, in Drawings, 129, 

139 
Wires, Electric Bell, Colouring, 138 
Wood Buildings, Colouring, 138 

, Colouring, in Drawings, 126-139 

Wooded Land, Representing, 152-153 
Writing on Drawings, 145, 146 
Wrought-iron, Colouring, in Drawings, 

132-139 
York Stone, Colouring, in Drawings, 128, 

139 
Zinc, Colouring, in Drawings, 139 



Printed by Casski-l and Company, Limitkd. Li dga^e Hill. London. E.G. 

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ENGINEER'S HANDY-BOOK. 

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FACTS, FORMULAE, TABLES AND QUESTIONS 

ON POWER, ITS GENERATION, TRANSMISSION AND MEASUREMENT; 
HEAT, FUEL AND STEAM ; THE STEAM-BOILER AND ACCESSORIES ; 
STEAM-ENGINES AND THEIR PARTS ; THE STEAM-ENGINE IN- 
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TOGETHER WITH A 

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BY 

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'* Roper's Hand-Book of the Locomotive," "Roper's Hand-Book of 
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FIFTEENTH EDITION. 
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^ixth (BAxtion, '^txvxitUn Hud (^xtMti 
Enlarged by 

EDWIN R. KELLER, M.E. 

AND 

CLAYTON W. PIKE, B.S. 
Ex-President of the Electrical Section of the Franklin Institute 



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